HORRIBLE SERVICE FROM UBER

I am long time uber customer, ordered a ride from Pretoria to Johannesburg, he dropped me off and I paid in cash. So a few days later I wanted to order, only to notice driver said i didnt pay and I now have an outstanding amount of R300 on my app. Notified Uber and nothing has been done, in the mean time i cannot use my app because I will not pay for something i already paid for. so frustrating, I do not recommend people use this app.