For whatever reason, WooCommerce is sending an email upon cancelled and failed orders only to the site admin. Now, although there must be a perfectly good reason why they decided not to offer the option to send these emails to customers as well, we won't debate about it but will simply provide you with the add-on that allows this.
This add-on doesn't have any settings and is installed like any other WordPress plugin. When installed and activated, it will simply send the same email to the customer just like it WooCommerce sends to the site admin upon failed or cancelled order. Needless to say, this plugin works only with WooCommerce and it will work regardless of whether the purchased product is Tickera ticket or not.