Poor service delivery

Hyundai Germiston took advantage of me by selling me a overpriced Creta Hyundai, after realising their bad service I wanted to exchange the car, they pretended to be assisting me only to find out they are buying time to suit their benefit. I tried several times to find a resolution but failed, I went as far as arranging with Mercedes polokoane to trade the car but Hyundai Germiston never prepared on their end, all I want is an exchange