diff --git a/app/controllers/spree/api/v2/storefront/checkout_controller_decorator.rb b/app/controllers/spree/api/v2/storefront/checkout_controller_decorator.rb
index 6f60d1a1..7683ecc5 100644
--- a/app/controllers/spree/api/v2/storefront/checkout_controller_decorator.rb
+++ b/app/controllers/spree/api/v2/storefront/checkout_controller_decorator.rb
@@ -17,6 +17,8 @@ def request_update_payment
               render_serialized_payload { serialize_resource(order) }
             else
               payment = find_payment(order, params[:payment_number])
+              return render_error_payload('Payment is void (refunded or canceled)') if payment.void?
+
               context = payment.request_update
 
               if context.success? && context.error_message.blank?
diff --git a/app/models/spree/gateway/payway_v2.rb b/app/models/spree/gateway/payway_v2.rb
index 434c487d..c55abf17 100644
--- a/app/models/spree/gateway/payway_v2.rb
+++ b/app/models/spree/gateway/payway_v2.rb
@@ -1,5 +1,5 @@
 module Spree
-  class Gateway::PaywayV2 < PaymentMethod
+  class Gateway::PaywayV2 < ::Spree::PaymentMethod
     # preference :endpoint, :string
     # preference :return_url, :string
     # preference :continue_success_url, :string
diff --git a/app/models/vpago/order_decorator.rb b/app/models/vpago/order_decorator.rb
index 371d8f87..efb98128 100644
--- a/app/models/vpago/order_decorator.rb
+++ b/app/models/vpago/order_decorator.rb
@@ -10,6 +10,7 @@ def self.prepended(base)
                     through: :line_items
 
       base.state_machine.before_transition from: :cart, do: :ensure_valid_vendor_payment_methods
+      base.state_machine.before_transition to: :complete, do: :generate_line_items_total_metadata
     end
 
     def ensure_valid_vendor_payment_methods
@@ -25,30 +26,6 @@ def line_items_from_same_vendor?
       line_items.joins(:variant).pluck('spree_variants.vendor_id').uniq.size == 1
     end
 
-    # Make sure the order confirmation is delivered when the order has been paid for.
-    def finalize!
-      # lock all adjustments (coupon promotions, etc.)
-      all_adjustments.each(&:close)
-
-      # update payment and shipment(s) states, and save
-      updater.update_payment_state
-
-      shipments.each do |shipment|
-        shipment.update!(self)
-        shipment.finalize! if paid? || authorized?
-      end
-
-      updater.update_shipment_state
-      save!
-      updater.run_hooks
-
-      touch :completed_at
-
-      deliver_order_confirmation_email if !confirmation_delivered? && (paid? || authorized?)
-
-      consider_risk
-    end
-
     def required_payway_payout?
       line_items.any?(&:required_payway_payout?) || shipments.any?(&:required_payway_payout?)
     end
@@ -90,29 +67,10 @@ def generate_line_items_total_metadata
       line_items.each(&:update_total_metadata)
     end
 
-    def send_confirmation_email!
-      return unless !confirmation_delivered? && (paid? || authorized?)
-
-      deliver_order_confirmation_email
-    end
-
-    def successful_payment
-      paid? || payments.any? { |p| p.after_pay_method? && p.authorized? }
-    end
-
-    alias paid_or_authorized? successful_payment
-
-    def authorized?
-      payments.last.authorized?
-    end
-
     def order_adjustment_total
       adjustments.eligible.sum(:amount)
     end
   end
 end
 
-if Spree::Order.included_modules.exclude?(Vpago::OrderDecorator)
-  Spree::Order.register_update_hook(:generate_line_items_total_metadata)
-  Spree::Order.prepend(Vpago::OrderDecorator)
-end
+Spree::Order.prepend(Vpago::OrderDecorator) if Spree::Order.included_modules.exclude?(Vpago::OrderDecorator)
diff --git a/app/models/vpago/payment/vpago_payment_processing_decorator.rb b/app/models/vpago/payment/vpago_payment_processing_decorator.rb
deleted file mode 100644
index 9f4f1415..00000000
--- a/app/models/vpago/payment/vpago_payment_processing_decorator.rb
+++ /dev/null
@@ -1,48 +0,0 @@
-module Vpago
-  module Payment
-    module VpagoPaymentProcessingDecorator
-      def process!
-        if vpago_type?
-          process_with_vpago_gateway
-        else
-          super
-        end
-      end
-
-      def cancel!
-        if vpago_type?
-          cancel_with_vpago_gateway
-        else
-          super
-        end
-      end
-
-      # private
-      def vpago_type?
-        payment_method.is_a?(Spree::Gateway::Payway) ||
-          payment_method.is_a?(Spree::Gateway::WingSdk) ||
-          payment_method.is_a?(Spree::Gateway::Acleda) ||
-          payment_method.is_a?(Spree::Gateway::PaywayV2)
-      end
-
-      def cancel_with_vpago_gateway
-        response = payment_method.cancel(transaction_id)
-        handle_response(response, :void, :failure)
-      end
-
-      def process_with_vpago_gateway
-        amount ||= money.money
-        started_processing!
-
-        response = payment_method.process(
-          amount,
-          source,
-          gateway_options
-        )
-        handle_response(response, :started_processing, :failure)
-      end
-    end
-  end
-end
-
-Spree::Payment.include(Vpago::Payment::VpagoPaymentProcessingDecorator)
diff --git a/app/models/vpago/payment_decorator.rb b/app/models/vpago/payment_decorator.rb
index fbbce9dd..09f731f1 100644
--- a/app/models/vpago/payment_decorator.rb
+++ b/app/models/vpago/payment_decorator.rb
@@ -3,16 +3,6 @@ module PaymentDecorator
     def self.prepended(base)
       base.has_many :payouts, class_name: 'Spree::Payout', inverse_of: :payment
       base.after_create -> { Vpago::PayoutsGenerator.new(self).call }, if: :should_generate_payouts?
-      base.after_update :capture_pre_auth, if: :state_changed_to_complete?
-      base.after_update :cancel_pre_auth, if: :state_changed_to_failed?
-    end
-
-    def state_changed_to_complete?
-      saved_change_to_state? && state == 'completed'
-    end
-
-    def state_changed_to_failed?
-      saved_change_to_state? && state == 'failed'
     end
 
     def should_generate_payouts?
@@ -23,41 +13,12 @@ def support_payout?
       payment_method.support_payout?
     end
 
-    # On the first call, everything works. The order is transitioned to complete and one Spree::Payment,
-    # which redirect the payment. But, after making the same call again,
-    # for instance because the payment wasn't completed or failed,
-    # another Spree::Payment is created but without a payment_url. So, if a consumer,
-    # for whatever reason, failed to complete the first payment, it would not be possible try again.
-    # This also meant that any consecutive Spree::Payment would not have a payment_url. The consumer is stuck
-
-    def build_source
-      return unless new_record?
-
-      return unless source_attributes.present? && source.blank? && payment_method.try(:payment_source_class)
-
-      self.source = payment_method.payment_source_class.new(source_attributes)
-      source.payment_method_id = payment_method.id
-      source.user_id = order.user_id if order
-
-      # Spree will not process payments if order is completed.
-      # We should call process! for completed orders to create a the gateway payment.
-      process! if order.completed?
-    end
-
     def request_update
       updater = payment_method.payment_request_updater.new(self, { ignore_on_failed: true })
       updater.call
       updater
     end
 
-    def authorized?
-      if source.is_a? Spree::VpagoPaymentSource
-        pending?
-      else
-        false
-      end
-    end
-
     def payment_url
       return unless payment_method.type_payway_v2?
 
diff --git a/lib/vpago/payment_status_marker.rb b/lib/vpago/payment_status_marker.rb
index c31748e3..bdd905ab 100644
--- a/lib/vpago/payment_status_marker.rb
+++ b/lib/vpago/payment_status_marker.rb
@@ -47,47 +47,35 @@ def update_payment_and_order
       else
         transition_to_failed!
       end
-
-      order_updater
     end
 
     def transition_to_paid!
       complete_payment!
       complete_order!
-      confirm_payouts!
     end
 
-    def transition_to_failed!
-      @payment.failure! unless @payment.failed?
-      @payment.order.update(state: 'payment')
-
-      notify_failed_payment
+    def complete_payment!
+      @payment.complete!
     end
 
-    def order_updater
-      @payment.order.update_with_updater!
-    end
+    def complete_order!
+      context = Spree::Checkout::Complete.new.call(order: @payment.order)
 
-    def complete_payment!
-      return if @payment.completed?
-
-      # not follow state machine rule when it manual
-      if @options[:updated_by_user_id].present?
-        ApplicationRecord.transaction do
-          @payment.state_changes.create!(previous_state: @payment.state, next_state: 'completed', name: 'payment')
-          @payment.update(state: 'completed')
-        end
+      if context.success?
+        @payment.capture_pre_auth
+        confirm_payouts!
       else
-        @payment.complete!
+        @error_message = context.error.value.full_messages.join(', ')
+        @payment.cancel_pre_auth
+        @payment.void!
       end
     end
 
-    def complete_order!
-      return if @payment.order.completed?
+    def transition_to_failed!
+      @payment.cancel_pre_auth
+      @payment.void!
 
-      order = @payment.order
-      order.finalize!
-      order.update(state: 'complete', completed_at: Time.zone.now)
+      notify_failed_payment
     end
 
     def payout_confirmed?
diff --git a/lib/vpago/payway_v2/payment_request_updater.rb b/lib/vpago/payway_v2/payment_request_updater.rb
index 59d5039e..f38b6d9f 100644
--- a/lib/vpago/payway_v2/payment_request_updater.rb
+++ b/lib/vpago/payway_v2/payment_request_updater.rb
@@ -4,22 +4,11 @@ class PaymentRequestUpdater < ::Vpago::PaymentRequestUpdater
       def call
         return if @payment.order.paid?
 
-        if items_eligible?
-          process_payment_status
-        else
-          mark_items_as_ineligible
-        end
+        process_payment_status
       end
 
       private
 
-      def mark_items_as_ineligible
-        @error_message = 'Items are not eligible due to insufficient stock'
-        marker_options = @options.merge(status: false, description:  @error_message)
-        marker = ::Vpago::PaymentStatusMarker.new(@payment, marker_options)
-        marker.call
-      end
-
       def process_payment_status
         checker = check_payway_status
 
@@ -38,9 +27,14 @@ def mark_payment_as_success(checker)
           payway_v2_response: checker.json_response,
           payout_total: checker.payout_total
         }
+
         marker_options = @options.merge(checker_result)
         marker = ::Vpago::PaymentStatusMarker.new(@payment, marker_options)
         marker.call
+
+        return unless marker.error_message&.present?
+
+        @error_message = marker.error_message
       end
 
       def mark_payment_as_failed(error_message)
@@ -56,10 +50,6 @@ def check_payway_status
         trans_status.call
         trans_status
       end
-
-      def items_eligible?
-        @payment&.order&.line_items&.all?(&:sufficient_stock?) == true
-      end
     end
   end
 end
diff --git a/spec/lib/vpago/payment_status_marker_spec.rb b/spec/lib/vpago/payment_status_marker_spec.rb
index 99fc5424..ef88b4de 100644
--- a/spec/lib/vpago/payment_status_marker_spec.rb
+++ b/spec/lib/vpago/payment_status_marker_spec.rb
@@ -11,6 +11,10 @@
   before do
     allow(checker).to receive(:check_transaction_url).and_return('https://checkout-sandbox.payway.com.kh/api/payment-gateway/v1/payments/check-transaction')
     VCR.use_cassette('payway_v2_check_transaction_status_0') { checker.call }
+
+    # skip validation
+    allow(payment.order).to receive(:ensure_line_items_present).and_return(true)
+    allow(payment.order).to receive(:delivery_required?).and_return(false)
   end
 
   describe '#call' do
diff --git a/spec/lib/vpago/payway_v2/payment_request_updater_spec.rb b/spec/lib/vpago/payway_v2/payment_request_updater_spec.rb
deleted file mode 100644
index d8a732c8..00000000
--- a/spec/lib/vpago/payway_v2/payment_request_updater_spec.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require 'spec_helper'
-
-RSpec.describe Vpago::PaywayV2::PaymentRequestUpdater, type: :model do
-  let(:gateway) { create(:payway_v2_gateway, auto_capture: true) }
-  let(:payment_source) { create(:payway_payment_source, payment_method: gateway) }
-  let(:user) { create(:user) }
-  let(:order) { OrderWalkthrough.up_to(:payment) }
-  let(:payment) { create(:payway_payment, payment_method: gateway, source: payment_source, order: order , state: 'processing') }
-
-  describe 'ineligible items' do
-    it 'marks the payment as failed due to insufficient stock' do
-      allow(order.line_items).to receive(:all?).and_return(false)
-      options = { updated_by_user_id: user.id }
-      updater = Vpago::PaywayV2::PaymentRequestUpdater.new(payment, options)
-      updater.call
-      
-      expect(payment.state).to eq('failed') 
-      expect(payment.source.payment_description).to eq('Items are not eligible due to insufficient stock') 
-    end
-  end
-end