UBER - Poor customer support taken extra cash and not refunding

I was riding to some event via uber cab on last Sunday night. I choose to google pay as I was on dropping gate of some *-star hotel. The driver asked me extra cash for some receipt and said its uber policy. I avoided argument as I had the trust that I can resolve such a small matter later directly with the company. But everything opposite happened when I complain the matter to the company the Uber straight away denied refunding the extra amount they charged during the trip and extra cash taken by their driver. As a customer we are helpless. It's not the matter of few bucks, it's about the trust breakage of the consumer.