Pronamic Pay status update notice by email.

pronamic-pay-status-update-notice.php

<?php
// Add below code to functions.php of your WordPress theme.

/**
 * Pronamic Pay status update notice.
 *
 * @param Payment $payment      The payment.
 * @param bool    $can_redirect Whether or not to redirect.
 * @param string  $old_status   Old paymet status.
 * @param string  $new_status   New payment status.
 */
function pronamic_pay_status_update_notice( $payment, $can_redirect, $old_status, $new_status ) {
	// Statuses to trigger notices for.
	$trigger_statuses = array(
		'Cancelled',
		'Expired',
		'Failure',
	);

	if ( ! in_array( $new_status, $trigger_statuses, true ) ) {
		// Status not in trigger statuses.
		return;
	}

	/*
	 * Send unsuccessful payment notice.
	 */

	// To.
	$to = get_option( 'admin_email' );

	// Subject.
	$subject = sprintf(
		'Unsuccessful payment #%s notice',
		$payment->get_id()
	);

	// Message.
	$message = sprintf(
		'A payment on %s has not been completed.',
		get_bloginfo( 'name' )
	);

	$message .= str_repeat( PHP_EOL, 2 );

	$message .= get_edit_post_link( $payment->get_id(), 'raw' );

	// Send message.
	wp_mail( $to, $subject, $message );
}

add_action( 'pronamic_payment_status_update', 'pronamic_pay_status_update_notice', 10, 4 );