diff --git a/includes/checkout.php b/includes/checkout.php
index c8a9e7e..bd1e105 100644
--- a/includes/checkout.php
+++ b/includes/checkout.php
@@ -184,7 +184,7 @@ function wcwp_get_order_weight($order_id)
 add_action('woocommerce_checkout_update_order_meta', 'wcwp_update_parcelshop_id');
 function wcwp_update_parcelshop_id($order_id)
 {
-    if (!empty($_POST['parcelshop_id']) && (isset($_POST['shipping_method'][0]) && 'wuunder_parcelshop' === sanitize_text_field($_POST['shipping_method'][0]))) {
+    if (!empty($_POST['parcelshop_id']) && isset($_POST['shipping_method']) && (isset($_POST['shipping_method'][0]) && 'wuunder_parcelshop' === sanitize_text_field($_POST['shipping_method'][0]))) {
         update_post_meta($order_id, 'parcelshop_id', sanitize_text_field($_POST['parcelshop_id']));
         WC()->session->__unset( 'WCWP_SELECTED_PARCELSHOP_ID' );
     }