Zomato — illicit charging of money

A product was not delivered to me worth rs 570. Then i asked for a refund but instead a promo code was added to my account and i wasn’t informed of the validity of this code and now the code has got expired and zomato is not updating it. This is not fair since the order was not delivered and i asked for refund to account but zomato advisor sent it as a promo code. They have charged me incorrectly when i have not even have used the services.