php add_action('init', 'update_customer_balance'); function update_customer_balance() { if (isset($_GET['https://www.smedslattentennis.com/kundsaldosussi/'])) { $customer_id = intval($_GET['customer_id']); $current_balance = get_field('saldo', 'user_' . $customer_id); if ($current_balance > 0) { update_field('saldo', $current_balance - 1, 'user_' . $customer_id); } } }