Complaint

I bought a car from Webuycars Silverton online and I was contacted to collect it. I drove the car for one day and realized that when u accelerate the car vibrate and start shaking, making a huge weird sound. The car didn't have a radio system as well as mobilize. The car feels unsafe and uncomfortable. I took it back the next day. They all took me from pillar to post refusing to take their car back and exchange it. It seems they were all aware and trying to get rid of it. They called their boss who tried to convince me to keep the car but I refuse. I left the car and the keys with them and they promised to sort out. They later called me and tell me they can't assist me I must go get a lawyer. They force me to take a car that they are all aware it not safe and uncomfortable. Why must I keep a car for 6 years thag I am not happy with? The customer service is so bad and they are bias. They communicate to one another in Afrikaans so you don't understand what they are saying. I want to exchange or cancel the deal if the can't help.