diff --git a/backend/app/plugins/wiaas/includes/admin/class-wiaas-admin-user-profile.php b/backend/app/plugins/wiaas/includes/admin/class-wiaas-admin-user-profile.php
index ba5b7b5..59fc0df 100644
--- a/backend/app/plugins/wiaas/includes/admin/class-wiaas-admin-user-profile.php
+++ b/backend/app/plugins/wiaas/includes/admin/class-wiaas-admin-user-profile.php
@@ -13,7 +13,7 @@ class Wiaas_Admin_Profile {
 
         $phone = $_POST['phone'];
 
-        if (!WC_Validation::is_phone($phone)){
+        if (!Wiaas_Validation_Functions::is_phone($phone)){
             $errors->add('phone_error', __( '<strong>ERROR</strong>: Enter valid phone number.', 'crf' ));
         };
 
diff --git a/backend/app/plugins/wiaas/includes/api/class-wiaas-rest-customer.php b/backend/app/plugins/wiaas/includes/api/class-wiaas-rest-customer.php
index 0507578..60c3594 100644
--- a/backend/app/plugins/wiaas/includes/api/class-wiaas-rest-customer.php
+++ b/backend/app/plugins/wiaas/includes/api/class-wiaas-rest-customer.php
@@ -148,7 +148,7 @@ class Wiaas_REST_Customer_API {
 			return wiaas_api_notice('ADD_PHONE_NUMBER', 'error', Wiaas_Customer::get_customer_info($customer_id));
 		}
 
-        if (!WC_Validation::is_phone($phone)){
+        if (!Wiaas_Validation_Functions::is_phone($phone)){
             return wiaas_api_notice('INVALID_PHONE_NUMBER', 'error', Wiaas_Customer::get_customer_info($customer_id));
         };
 
diff --git a/backend/app/plugins/wiaas/includes/class-wiaas-validation-functions.php b/backend/app/plugins/wiaas/includes/class-wiaas-validation-functions.php
new file mode 100644
index 0000000..9988b67
--- /dev/null
+++ b/backend/app/plugins/wiaas/includes/class-wiaas-validation-functions.php
@@ -0,0 +1,13 @@
+<?php
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Class Wiaas_Validation_Functions
+ */
+class Wiaas_Validation_Functions {
+
+    public static function is_phone($phone){
+        return WC_Validation::is_phone($phone);
+    }
+}
diff --git a/backend/app/plugins/wiaas/wiaas.php b/backend/app/plugins/wiaas/wiaas.php
index 5bafd13..b2d0fe1 100644
--- a/backend/app/plugins/wiaas/wiaas.php
+++ b/backend/app/plugins/wiaas/wiaas.php
@@ -59,6 +59,8 @@ include_once WIAAS_DIR . '/includes/class-wiass-templates.php';
 
 include_once WIAAS_DIR . '/includes/wiaas-class-measurement-units.php';
 
+include_once WIAAS_DIR . '/includes/class-wiaas-validation-functions.php';
+
 function wiaas_redirect_to_login() {
     wp_safe_redirect(get_site_url('', 'wp-login.php'));
 }