Force to pay for a repair I didn’t cause.

I bought a 2015 manual Audi A1 from the East London Centre in July 2017. They promised they had done a 360 check on the car but this car has given me two problems already. First it had CV joint problems and had to go in for repairs. That was fine with me because at least I didn’t have to pay for anything. It is however the second problem we’re in loggerheads with Audi South Africa. I was driving on a freeway on gear 5 doing around 100km/h when suddenly the gear slipped off and the car stopped taking gears. I called them and explained what had happened and the came and collected the gear and took it in for a check up. Two days later they called and told me that the cars clutch had burnt and Audi SA does not cover a burnt clutch. I have had two cars before this one, a Toyota Etios, and later a Polo Vivo, non of which has ever burnt a clutch. I even offered asking Car Track to give them data from that day but they refuse to assist me. Instead I get a R23000+ Repair bill. Very bitter pill to swallow when you know very well that this has everything to do with the cars gear box malfunctioning.