Uber eats is out to rob people

On the first of November I had an order where I was supposed to get change from my cash payment but the delivery guy added the change to my credits. Yesterday I ordered from uber eats again and my order amounted to R71. They took the whole R71 from my account and also took my money that was sitting on credits. Now I sent them a query they plain out deny to over charge me despite me sending them screenshots.