Dissatisfied in App/service

Very dissatisfied with Checkers Sixty60 delivery this morning We order alot on the app however this morning did not go well Delivery driver arrives, tub of ice-cream leaking out of container Aromat container open in bag, bag full of Aromat Order item 3 for 2 dishwasher tablets, only two arrive, pay full price for two Sure I order 3 on app, however not the first time I order item on app only to find subsequent to delivery item did not arrive, go back on app and notice item was not chosen. Now I have to pay full price for two of the (3 for 2) items and Checkers Malmesbury does not entertain my complaint. Why would one order two items and pay full price whereas one can(in this case) order two items a day get one free, makes no sense but I guess they do not understand.