Car dealership

I bought a car at Hyundai Benoni and a week later my documents were used to apply for another car without my knowledge and I have then tried talking to them to remove the other car and nothing happened and then I asked if they can exchange the car I bought for me cause it was given to me and it had faults and broken windscreen and was told it will be changed and they never did till I took it back. And Im paying for it.