Car given with tyres that have no tread at all.

I bought a car for Hyundai Brackenfell in april 2015 and almost two months later my friend point out the back tyres tread to me. I then get in contact with the salesman who sold me this car, He request the pictures of the tyres and to date i only get emails that they working on it, But no-one from the dealership ever called me to tell me exactly what is happening. I Thought that buying a car from HYUNDAI would give me peace of mind as they are supposed to be a reputable dealership. I went to HYUNDAI because i knew the FNI from THE HYUNDAI PLUMBSTEAD branch and she was always a very professional person to deal with. but as for the rest of the used vehicle department from manager down are all the worst i have ever seen in the car sales industry. I guest what they give to people doesnt matter to them as long as they get your money and thier salaries are paid us as custormers may go to hell.