Uber SA, wake up!!! Your drivers are cheating people out of money

Uber SA does not have a contact number so I sent a message on Facebook about 2 of the drivers, the first one picked me up dropped me off and I paid the R39, after he dropped me he canceled the trip and I received a message of a cancelation fee of R25, which uber then refunded, so with my second trip the fee was R31, I then paid R50 because the driver did not have change, so I received my receipt and saw that the trip was actually R6 because the R25 was deducted, so I'm very upset and not receiving any feedback from Uber. The drivers are not honest. I'm really disappointed with Uber as I use their service so many times.