diff --git a/modules/gateways/xendit/hooks.php b/modules/gateways/xendit/hooks.php
index e34df1e..b0fe65a 100644
--- a/modules/gateways/xendit/hooks.php
+++ b/modules/gateways/xendit/hooks.php
@@ -1,30 +1,42 @@
 <?php
+/**
+ * Register hook function call.
+ *
+ * @param string $hookPoint The hook point to call.
+ * @param integer $priority The priority for the hook function.
+ * @param string|function The function name to call or the anonymous function.
+ *
+ * @return This depends on the hook function point.
+ */
 
-use Xendit\Lib\ActionBase;
-use Xendit\Lib\Recurring;
+if (!defined('WHMCS')) {
+    die('You cannot access this file directly.');
+}
 
 /**
- * Hook invoice created
+ * Hook invoice creation
  *
  * @param $vars
- * @return void
+ * @return array|void
  */
-add_hook('InvoiceCreation', 1, function ($vars) {
-    if ($vars['status'] == 'Draft') {
-        return;
-    }
+function hookInvoiceCreation($vars)
+{
+    if ($vars['status'] !== 'Draft' && class_exists('\Xendit\Lib\Recurring')) {
+        $xenditRecurring = new \Xendit\Lib\Recurring();
+        $invoice = $xenditRecurring->getInvoice($vars['invoiceid']);
 
-    $xenditRecurring = new Recurring();
-    $invoice = $xenditRecurring->getInvoice($vars['invoiceid']);
+        // if payment method is Xendit
+        if ($invoice->paymentmethod != $xenditRecurring->getDomainName()) {
+            return;
+        }
 
-    // if payment method is Xendit
-    if ($invoice->paymentmethod != $xenditRecurring->getDomainName()) {
-        return;
+        // Save xendit transaction
+        return $xenditRecurring->storeTransactions($vars['invoiceid']);
     }
+}
+
+add_hook('InvoiceCreation', 1, 'hookInvoiceCreation');
 
-    // Save xendit transaction
-    $xenditRecurring->storeTransactions($vars['invoiceid']);
-});
 
 /**
  * Hook to show Xendit payment gateway based on currency
@@ -32,13 +44,18 @@
  * @param $vars
  * @return array|void
  */
-add_hook("ClientAreaPageCart", 1, function ($vars) {
-    if ($vars['templatefile'] == 'viewcart') {
-        $actionBase = new ActionBase();
+function hookClientAreaPageCart($vars)
+{
+    if ($vars['templatefile'] == 'viewcart' && class_exists('\Xendit\Lib\ActionBase')) {
+        $actionBase = new \Xendit\Lib\ActionBase();
         $activeCurrency = $vars['currency']['code'] ?? $vars['activeCurrency']->code;
-        if (!$actionBase->validateCompatibilityVersion() || !in_array($activeCurrency, ActionBase::ALLOW_CURRENCIES)) {
+        if (!$actionBase->validateCompatibilityVersion()
+            || !in_array($activeCurrency, \Xendit\Lib\ActionBase::ALLOW_CURRENCIES)
+        ) {
             unset($vars['gateways']["xendit"]);
         }
     }
     return $vars;
-});
+}
+
+add_hook("ClientAreaPageCart", 1, 'hookClientAreaPageCart');