from my third world fast food delivery experience, you should check the contents as soon as they deliver the food and refuse to pay for something written in the receipt that did not come with your order. if something is missing, too bad, but at least you won't have to pay for it. you can also refuse to accept. but only if you don't have a heart for your fellow overworked, underpaid employees who might shoulder this loss through salary deduction.

regardless of whether they made a mistake or not, you should not have paid in the first place because it's like an acknowledgment that everything is complete. it finishes your transaction. it's an operational risk on their part to deliver goods that you claim were not delivered the first time around because it is quite possible that some people would make false claims.