yeah in my experience as an embarrassingly regular user of uber if you paid money for an item, and there's a problem with it, the refund always comes through and it's normally quite generous too - more than the in store price on a drink in a combo for example.

I did have a "double bbq bacon cheeseburger" free with $25 purchase at burger king, which was in the delivery bag a regular cheeseburger (with ketchup) instead, not get a refund despite being an incorrect item. So I guess if Burger King was deliberately misdelivering the wrong, cheaper burger with their giveaway offer, they can game the system.