Bad service at mercedes benz

Very frustrated & don't see myself going or referring anyone to mercedes umhlanga...I bought a c200 in November last year, it had 26000km, this month I took the car to tygerwheels for a scratch in the rim, they advised me that the 2 front tyers are worn out & even have threads, and they are a safety risk..I phoned merceds benz to enquire why they sold me a car with such old bad tyers & was told that I have travelled 10 000km already with the car so they won't change those tyers for me. They said they can give me their internal rate on buying tyers