/**
 * Executed when the status is changed to failed.
 * @param int $order_id
 * @param WC_Order $order
 */
function wpdg_9291_woocommerce_order_status_failed($order_id, $order) {
    // Do something here
}
add_action('woocommerce_order_status_failed', 'wpdg_9291_woocommerce_order_status_failed', 15, 2);