Horrible customer service!

Bought a pizza which took like 30min just to order because the cashier was a trainee with no supervisor assisting her, all the staff walking around in the shop and received a voucher for a store not in my province. Proceeded to add items to my cart only to find out that shipping cost more than the voucher itself and the voucher code was invalid. I then emailed the company to change the voucher to another store who is also a participating partner and code and explained my situation only to receive apparent instructions to order which I did. Emailed them back to say that's exactly what I did and did not receive a reply since then. Horrible service. I will never buy debonairs ever again.