Uber bad service

I heard some customers talking that Uber has a bad service of overcharging card payments transactions and other customers being charged for rides they did not use yet can't be assisted appropriate. This time around I got to experience the bad service whereby I was charged R40 by the end of trip and was also sent an email showing I have a promotion. After some time when then boom I receive the email that I owe Uber and did not pay the full amount for the ride which was supposed to be R63. I tried contacting the customer service but their programmed robot cannot assist.