Audi Alignment Problem

I bought a used (3 years old) Audi A4. Within 6 months I had to replace all four tyres! I informed the salesman, Raymond Leesman, after two months that there was a problem but he told me that I was not used to the Quattro system. I kept contacting him until finally I took the car for alignment. Too late, the alignment was out and all 4 tyres were worn to the wire on the insides. I wrote to Audi SA and the dealer principal. The dealer principal didn't even bother to reply. Audi SA tell me yhey have no control over the dealerships!!! Once again the corporate giant wins. I will never buy Audi again.