Short items and refund after 24hrs or 48hrs

I am very unhappy with Checkers 60, I placed an order last night for delivery this morning, the items I ordered were for an event today where I was supposed to cook make burger meals for 50 under privileged children. Next thing they deliver only 2 packs of 6, no report on the shortage or anything. I go on to the app to request a refund so that I can order again, they only refund me 19,99 which is a price for one pack of 6. I call their call centre asking them to just deliver the rolls as it was their mistake and I am not really keen to pay another delivery fee, hey say they cant do that they can refund me the delivery fee instead but the refund can only reflect in 24 or 48hrs. What the heck what are the kids supposed to eat until then? I state my unhappiness and the implications they can only escalate the matter, next thing they eventually refund me this afternoon minus the delivery fee so. I am soooo angry because their mistake is costing me now as I had to order and pay another delivery fee.