Cheated out of a special deal

The uber eats app showed buy one get one free deal on McDonald's jalepino fries.( I have a screenshot and even a video). But I never got my free fries and when I complained uber eats said sorry they could not do anything for me. I spoke to McDonald's who said the deal does not show with them. But are they not responsible to make sure their deals are correct. I should've just ordered from Kentucky