diff --git a/app/controllers/Woocommerce_controller.php b/app/controllers/Woocommerce_controller.php
index e1f3445..d54e64c 100644
--- a/app/controllers/Woocommerce_controller.php
+++ b/app/controllers/Woocommerce_controller.php
@@ -46,12 +46,19 @@ class PEPPOL_Woocommerce_controller {
     public static function post_payment(int $order_id): void {
         $order_id = (int) $order_id;
 
+        global $wpdb;
+
         if ($order_id <= 0) {
             return;
         }
 
         $order = \wc_get_order($order_id);
 
+        $is_invoice_exists = $wpdb->get_var($wpdb->prepare("SELECT COUNT(*) FROM {$wpdb->prefix}esi_peppol_invoices WHERE order_id = %d", $order_id));
+        if ($is_invoice_exists > 0) {
+            return;
+        }
+
         if (!$order instanceof \WC_Order) {
             return;
         }