diff --git a/src/include/class-wc-retailcrm-loyalty.php b/src/include/class-wc-retailcrm-loyalty.php
index f6eb2fb..67ab5d7 100644
--- a/src/include/class-wc-retailcrm-loyalty.php
+++ b/src/include/class-wc-retailcrm-loyalty.php
@@ -432,24 +432,22 @@ if (!class_exists('WC_Retailcrm_Loyalty')) :
 
             $response = $this->apiClient->ordersGet($orderExternalId);
 
-            if (!$response instanceof WC_Retailcrm_Response || !$response->isSuccessful()) {
-                writeBaseLogs('Process order: Error when receiving an order from the crm. Order Id: ' . $orderExternalId);
+            if (!$response instanceof WC_Retailcrm_Response || !$response->isSuccessful() || !isset($response['order'])) {
+                writeBaseLogs('Process order: Error when receiving an order from the CRM. Order Id: ' . $orderExternalId);
 
                 return [];
             }
 
-            if (isset($response['order'])) {
-                foreach ($response['order']['items'] as $item) {
-                    $externalId = $item['externalIds'][0]['value'];
-                    $externalId = preg_replace('/^\d+\_/m', '', $externalId);
-                    $crmItems[$externalId] = $item;
+            foreach ($response['order']['items'] as $item) {
+                $externalId = $item['externalIds'][0]['value'];
+                $externalId = preg_replace('/^\d+\_/m', '', $externalId);
+                $crmItems[$externalId] = $item;
 
-                    if (!$discountType) {
-                        foreach ($item['discounts'] as $discount) {
-                            if (in_array($discount['type'], ['bonus_charge', 'loyalty_level'])) {
-                                $discountType = $discount['type'];
-                                break;
-                            }
+                if (!$discountType) {
+                    foreach ($item['discounts'] as $discount) {
+                        if (in_array($discount['type'], ['bonus_charge', 'loyalty_level'])) {
+                            $discountType = $discount['type'];
+                            break;
                         }
                     }
                 }
diff --git a/src/include/class-wc-retailcrm-orders.php b/src/include/class-wc-retailcrm-orders.php
index 9d0abb0..7bda5ae 100644
--- a/src/include/class-wc-retailcrm-orders.php
+++ b/src/include/class-wc-retailcrm-orders.php
@@ -102,22 +102,23 @@ if (!class_exists('WC_Retailcrm_Orders')) :
                 $wcOrder = wc_get_order($orderId);
 
                 if ($this->loyalty) {
+                    $wcCustomer = null;
                     $privilegeType = 'none';
                     $discountLp = $this->loyalty->deleteLoyaltyCouponInOrder($wcOrder);
-                    $data = $wcOrder->get_data();
+                    $dataOrder = $wcOrder->get_data();
 
-                    if (isset($data['customer_id'])) {
-                        $wcCustomer = new WC_Customer($data['customer_id']);
+                    if (isset($dataOrder['customer_id'])) {
+                        $wcCustomer = new WC_Customer($dataOrder['customer_id']) ?? null;
                     }
 
-                    if (!$this->loyalty->isValidOrder($wcCustomer ?? null, $wcOrder)) {
+                    if (!$this->loyalty->isValidOrder($wcCustomer, $wcOrder)) {
                         if ($discountLp > 0) {
                             writeBaseLogs('The user does not meet the requirements for working with the loyalty program. Order Id: ' . $orderId);
                         }
 
                         $discountLp = 0;
                         $privilegeType = 'none';
-                    } elseif ($this->loyalty->isValidUser($wcCustomer ?? null)) {
+                    } elseif ($this->loyalty->isValidUser($wcCustomer)) {
                         $privilegeType = 'loyalty_level';
                     }
                 }
diff --git a/src/include/order/class-wc-retailcrm-order-item.php b/src/include/order/class-wc-retailcrm-order-item.php
index c25f955..53e593a 100644
--- a/src/include/order/class-wc-retailcrm-order-item.php
+++ b/src/include/order/class-wc-retailcrm-order-item.php
@@ -115,7 +115,7 @@ class WC_Retailcrm_Order_Item extends WC_Retailcrm_Abstracts_Data
      * @param WC_Order_Item_Product $item
      * @param $price
      * @param int $decimalPlaces Price rounding from WC settings
-     *
+     * @param array|null $crmItem Current trade position in CRM
      * @return float|int
      */
     private function calculateDiscount(
@@ -135,6 +135,9 @@ class WC_Retailcrm_Order_Item extends WC_Retailcrm_Abstracts_Data
                 }
             }
 
+            /**
+             * The loyalty program discount is calculated within the CRM system. It must be deleted during transfer to avoid duplication.
+             */
             $productPrice = ($item->get_total() / $item->get_quantity()) + ($loyaltyDiscount / $crmItem['quantity']);
 
             if ($this->cancelLoyalty) {
@@ -171,10 +174,19 @@ class WC_Retailcrm_Order_Item extends WC_Retailcrm_Abstracts_Data
         $this->cancelLoyalty = $cancelLoyalty;
     }
 
+    /**
+     * Checking whether the loyalty program discount needs to be canceled. (Changing the sales items in the order)
+     *
+     * @param array $wcItems
+     * @param array $crmItems
+     *
+     * @return bool
+     */
     public function isCancelLoyalty($wcItems, $crmItems): bool
     {
         $loyaltyDiscount = 0;
 
+        /** If the number of sales items does not match */
         if (count($wcItems) !== count($crmItems)) {
             $this->cancelLoyalty = true;
 
@@ -182,12 +194,14 @@ class WC_Retailcrm_Order_Item extends WC_Retailcrm_Abstracts_Data
         }
 
         foreach ($wcItems as $id => $item) {
+            /** If a trading position has been added/deleted */
             if (!isset($crmItems[$id])) {
                 $this->cancelLoyalty = true;
 
                 return true;
             }
 
+            /** If the quantity of goods in a trade item does not match */
             if ($item->get_quantity() !== $crmItems[$id]['quantity']) {
                 $this->cancelLoyalty = true;
 
@@ -202,6 +216,10 @@ class WC_Retailcrm_Order_Item extends WC_Retailcrm_Abstracts_Data
                 }
             }
 
+            /**
+             *If the sum of the trade item including discounts and loyalty program discount exceeds the cost without discounts.
+             * (Occurs when recalculating an order, deleting/adding coupons)
+             */
             if (($item->get_total() + $loyaltyDiscount) > $item->get_subtotal()) {
                 $this->cancelLoyalty = true;
 
diff --git a/tests/test-wc-retailcrm-loyalty.php b/tests/test-wc-retailcrm-loyalty.php
index c511081..8e53969 100644
--- a/tests/test-wc-retailcrm-loyalty.php
+++ b/tests/test-wc-retailcrm-loyalty.php
@@ -330,6 +330,7 @@ class WC_Retailcrm_Loyalty_Test extends WC_Retailcrm_Test_Case_Helper
     {
         $products = DataLoyaltyRetailCrm::createProducts();
         $user = DataLoyaltyRetailcrm::createUsers()[0];
+        $discountLoyalty = 50;
 
         $wcOrder = wc_create_order([
             'status'        => null,
@@ -391,7 +392,7 @@ class WC_Retailcrm_Loyalty_Test extends WC_Retailcrm_Test_Case_Helper
         $this->setMockResponse($this->apiMock, 'applyBonusToOrder', $response);
         $this->loyalty = new WC_Retailcrm_Loyalty($this->apiMock, []);
 
-        $this->loyalty->applyLoyaltyDiscount($wcOrder, $createdCrmOrderResponse, 50);
+        $this->loyalty->applyLoyaltyDiscount($wcOrder, $createdCrmOrderResponse, $discountLoyalty);
 
         foreach ($wcOrder->get_items() as $id => $item) {
             $this->assertNotEquals($item->get_total(), $currentItemsPrice[$id]);
@@ -456,7 +457,7 @@ class WC_Retailcrm_Loyalty_Test extends WC_Retailcrm_Test_Case_Helper
             ]
         ];
 
-        $this->loyalty->applyLoyaltyDiscount($wcOrder, $createdCrmOrderResponse, 0);
+        $this->loyalty->applyLoyaltyDiscount($wcOrder, $createdCrmOrderResponse);
 
         foreach ($wcOrder->get_items() as $id => $item) {
             $this->assertNotEquals($item->get_total(), $currentItemsPrice[$id]);