Failed Mr Delivery order

I had a coupon for a 60 rand off when i purchase food for more than 100 ZAR , i did than ordered from KFC ferndale via the MRD app and my order no. Was DFD***9. After waiting for over an hour ,the delivery was unsuccessful with no explanation and we were told to create another order. This meant the coupon has already been used. And cant be used again. Poor service delivery!