Sending email to customer on cancelled order in Woocommerce

In this custom function hooked in woocommerce_order_status_changed action hook, I am targeting "cancelled" and "failed" orders sending an the corresponding email notification to the customer (as admin will receive it on his side by WooCommerce automated notifications):

add_action('woocommerce_order_status_changed', 'send_custom_email_notifications', 10, 4 );function send_custom_email_notifications( $order_id, $old_status, $new_status, $order ){    if ( $new_status == 'cancelled' || $new_status == 'failed' ){        $wc_emails = WC()->mailer()->get_emails(); // Get all WC_emails objects instances        $customer_email = $order->get_billing_email(); // The customer email    }    if ( $new_status == 'cancelled' ) {        // change the recipient of this instance        $wc_emails['WC_Email_Cancelled_Order']->recipient = $customer_email;        // Sending the email from this instance        $wc_emails['WC_Email_Cancelled_Order']->trigger( $order_id );    }     elseif ( $new_status == 'failed' ) {        // change the recipient of this instance        $wc_emails['WC_Email_Failed_Order']->recipient = $customer_email;        // Sending the email from this instance        $wc_emails['WC_Email_Failed_Order']->trigger( $order_id );    } }

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This should works in WooCommerce 3+

If you need, instead of changing the email, you can add it, to existing recipients:

// Add a recipient in this instance$wc_emails['WC_Email_Failed_Order']->recipient .= ',' . $customer_email;

Related answer: Send an email notification when order status change from pending to cancelled