diff --git a/app/controllers/eis_billing/invoices_controller.rb b/app/controllers/eis_billing/invoices_controller.rb
index 81ff9b9888..23a64c83ff 100644
--- a/app/controllers/eis_billing/invoices_controller.rb
+++ b/app/controllers/eis_billing/invoices_controller.rb
@@ -1,15 +1,8 @@
 module EisBilling
   class InvoicesController < BaseController
-    TYPE = 'PaymentOrders::EveryPay'.freeze
-    PAID = 'paid'.freeze
-    CANCELLED = 'cancelled'.freeze
-    ISSUED = 'unpaid'.freeze
-    FAILED = 'failed'.freeze
-
     before_action :load_invoice, only: :update
 
     def update
-      # if @invoice.update(modified_params) && payment_orders_handler
       state = InvoiceStateMachine.new(invoice: @invoice, status: params[:status])
       if @invoice.update(modified_params) && state.call
         render json: {
@@ -26,42 +19,6 @@ def update
 
     private
 
-    # def payment_orders_handler
-    #   return false if @invoice.cancelled? && status.paid? || @invoice.cancelled? && status.issued?
-    #   return false if @invoice.paid? && (status.failed? || status.cancelled?)
-
-    #   case 
-    #   when @invoice.paid? && status.paid?
-    #     true
-    #   when @invoice.unpaid? && status.issued?
-    #     true
-    #   when @invoice.cancelled? && (status.cancelled? || status.failed?)
-    #     true
-    #   when status.issued?
-    #     @invoice.cancel_manualy
-    #   when status.paid?
-    #     @invoice.autobind_manually
-    #   else
-    #     @invoice.cancel
-    #   end
-    # end
-
-    # def status
-    #   status = case params[:status]
-    #            when 'paid'
-    #              'paid'
-    #            when 'cancelled'
-    #              'cancelled'
-    #            when 'failed'
-    #              'failed'
-    #            else
-    #              'unpaid'
-    #            end
-
-    #   Struct.new(:paid?, :cancelled?, :issued?, :failed?)
-    #         .new(status == PAID, status == CANCELLED, status == ISSUED, status == FAILED)
-    # end
-
     def load_invoice
       @invoice = Invoice.find_by(number: params[:invoice][:invoice_number])
       return if @invoice.present?
diff --git a/app/models/invoice_state_machine.rb b/app/models/invoice_state_machine.rb
index 210263a579..cd1886665f 100644
--- a/app/models/invoice_state_machine.rb
+++ b/app/models/invoice_state_machine.rb
@@ -1,5 +1,3 @@
-# enum status: %i[unpaid paid cancelled failed]
-
 class InvoiceStateMachine
   attr_reader :invoice, :status
 
@@ -24,21 +22,24 @@ def call
   private
 
   def mark_as_paid
-    return push_error unless invoice.payable? || invoice.paid?
+    return push_error unless invoice.payable?
+    return true if invoice.paid?
 
     invoice.autobind_manually
     invoice
   end
 
   def mark_as_cancel
-    return push_error unless invoice.cancellable? || invoice.cancelled?
+    return push_error unless invoice.cancellable?
+    return true if invoice.cancelled?
 
     invoice.cancel
     invoice
   end
 
   def mark_as_unpaid
-    return push_error if invoice.paid? || !invoice.cancellable?
+    return push_error if invoice.paid? && invoice.payment_orders.last.payment_reference? || invoice.cancelled?
+    return true unless invoice.paid?
 
     invoice.cancel_manualy
     invoice
diff --git a/app/models/payment_order.rb b/app/models/payment_order.rb
index fd66843476..5e7069e1be 100644
--- a/app/models/payment_order.rb
+++ b/app/models/payment_order.rb
@@ -64,6 +64,10 @@ def self.supported_method?(name, shortname: false)
     false
   end
 
+  def payment_reference?
+    response && response['payment_reference'].present?
+  end
+
   def base_transaction(sum:, paid_at:, buyer_name:)
     BankTransaction.new(
       description: invoice.order,
diff --git a/app/models/payment_orders/every_pay.rb b/app/models/payment_orders/every_pay.rb
index 15526e4d7d..2695c20e0f 100644
--- a/app/models/payment_orders/every_pay.rb
+++ b/app/models/payment_orders/every_pay.rb
@@ -30,10 +30,6 @@ def valid_response_from_intermediary?
       valid_hmac? && valid_amount? && valid_account?
     end
 
-    def payment_reference?
-      response['payment_reference'].present?
-    end
-
     def settled_payment?
       SUCCESSFUL_PAYMENT.include?(response['payment_state'])
     end
diff --git a/test/models/invoice_state_machinte_test.rb b/test/models/invoice_state_machinte_test.rb
new file mode 100644
index 0000000000..319da1aa2d
--- /dev/null
+++ b/test/models/invoice_state_machinte_test.rb
@@ -0,0 +1,105 @@
+require 'test_helper'
+
+class InvoiceTest < ActiveSupport::TestCase
+  include ActionMailer::TestHelper
+
+  setup do
+    @invoice = invoices(:one)
+    @unpaid = invoices(:unpaid)
+
+    stub_request(:post, 'https://eis_billing_system:3000/api/v1/invoice_generator/invoice_status')
+      .with(
+        body: '{"invoice_number":2,"status":"paid"}'
+      )
+      .to_return(status: 200, body: '', headers: {})
+  end
+
+  def test_unpaid_invoice_can_be_change_status_to_paid
+    assert !@unpaid.paid?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'paid').call
+    @unpaid.reload
+
+    assert @unpaid.paid?
+  end
+
+  def test_no_any_errors_if_invoice_with_unpaid_status_set_again_unpaid
+    assert !@unpaid.paid?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'unpaid').call
+    @unpaid.reload
+
+    assert !@unpaid.paid?
+    assert @unpaid.errors.empty?
+  end
+
+  def test_only_unpaid_invoice_can_be_cancelled
+    assert !@unpaid.paid?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'cancelled').call
+    @unpaid.reload
+
+    assert @unpaid.cancelled?
+
+    assert @invoice.paid?
+    InvoiceStateMachine.new(invoice: @invoice, status: 'cancelled').call
+    @invoice.reload
+
+    assert_equal @invoice.errors.full_messages.join, 'Inavalid state cancelled'
+    assert @invoice.errors.present?
+  end
+
+  def test_cancelled_invoiced_cannot_be_unpaid
+    assert !@unpaid.paid?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'cancelled').call
+    @unpaid.reload
+
+    assert @unpaid.cancelled?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'unpaid').call
+    @unpaid.reload
+
+    assert @unpaid.cancelled?
+
+    assert @unpaid.errors.present?
+    assert_equal @unpaid.errors.full_messages.join, 'Inavalid state unpaid'
+  end
+
+  def test_if_paid_invoice_not_have_response_from_everypay_it_can_be_unpaid_back
+    assert !@unpaid.paid?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'paid').call
+    @unpaid.reload
+
+    assert @unpaid.paid?
+    assert_nil @unpaid.payment_orders.last.payment_reference?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'unpaid').call
+    @unpaid.reload
+
+    assert !@unpaid.paid?
+  end
+
+  def test_if_paid_invoice_has_response_from_everypay_it_cannot_be_rollback
+    assert !@unpaid.paid?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'paid').call
+    @unpaid.reload
+
+    assert @unpaid.paid?
+    payment_order = @unpaid.payment_orders.last
+    payment_order.response = {}
+    payment_order.response[:payment_reference] = 'responsefromeveryapy'
+    payment_order.save && payment_order.reload
+
+    assert @unpaid.payment_orders.last.payment_reference?
+
+    InvoiceStateMachine.new(invoice: @unpaid, status: 'unpaid').call
+    @unpaid.reload
+
+    assert @unpaid.paid?
+    assert @unpaid.errors.present?
+    assert_equal @unpaid.errors.full_messages.join, 'Inavalid state unpaid'
+  end
+end