UberEats does not refund for items not delivered! Face value bad service!

I purchased a deal where you buy one and get one for free. We purchased 2 chili cheese burgers, 2 chicken burgers and 2 chili cheese fries. Uber eats only delivered the 4 burgers and NO chips. They then stated that they apologise for not delivering the second chips portion and credited my account out of good will!!!! They did not deliver Anything. The credit was loaded and the next moment the credit was missing. Now they say that they are sorry for this bad experience but cannot give me more price adjustments / credits. Since WHEN does a customer buy something and when they do not get it the company just keeps the money. It is a small amount but based on principal it is disgusting. I am appalled by this !