Avis - Cant be trusted

I have been renting cars for 40 years, over 200 in that time and never had a problem. I'm so sorry I did not go to Hello Peter before hiring a car from Avis. I reported a remote control problem with the car, it would not lock or open, took it back on a Saturday, the manager said he will get me a new car on Monday,but 7 days later still no car. If the car was ****** (VW Polo) they would have made me pay for it. I returned the car to their Rivonia branch, and Lukas inspected the car and said it was fine. The next day they called me to say that I am responsible for the stone chips on the front bumper. I thought fair wear and tear was acceptable, the car already had other marks on it. I checked 2 other similar models in their car park and found them to have the same problem. And they were old stone chips. Without any communication, they debited my CC with R2,950 week. I sent Customer Services a letter of complaint 7 days ago, NO RESPONSE. I can see a huge fight coming. I should have asked for a written report.