Sold a faulty car

Purchased car 28/04/15 and was not told of any issues. I drove it a few days and heard a strange knocking sound which I mentioned to them and was told by Divan(dealer) that he already experienced it himself and thinks its the lower control arm. After lifting the car I found the tie rod end had been sprayed yellow by roadworthy but it had still been passed. There is definitely some sort of agreement between the place they use for roadworthy and themselves to pass such vehicles. They also did not renew my license when I purchased the car and did so after 6 months and x2 traffic fines later. Car had to be sent for another roadworthy test for licence renewal and again was passed with a broken tail light and issues with wipers. I had spent R8600 on sorting out issues ive had after being turned away from their mechanic. You become an irritation to them with their quick replies on the phone to get you off. Now I have blown my motor 9 days after the benchmark date for my 6 months warranty with them and they will not assist. Do not buy from them, they have ******* practises with roadworthy and known for selling faulty cars. x4 friends of mine have been done in by them aswell. BIG MISTAKE!