Audi Quote R150 000 - repair for R10 000

My Audi A4 broke down - no gears. Audi Centre Somerset West, where I did all my services, were nearby and I called them. They towed my car for about 15 km behind another car to their garage. According to my knowledge and other Audi Centre's this is not allowed. They did not offer me any car as alternative while they check my car. After two days, they contacted me that my gearbox has internal damage and they need to put in a new gearbox. Quote - R150 000. My car has 114000 km on the clock - out of warranties. I did all my services at Audi Centre on time - no oil leakages was seen. I contacted Audi SA to ask for goodwill and for them to take my hand because I cannot afford this. After 10 days and after they called me to tell me that they will help me I received a letter stating that they cannot assist me in any way! I delivered my car to another service provider. After a week and R10 000 my car was repaired and I was driving again. How absurd - R150 000 vs R10000??? My trust in Audi is gone - both Audi Centre Somerset West as well as Audi SA.