Pathetic service

I bought a car and pay cash. A RATED GOLD🥇 As we drove out the drivetrain light went on and can't drive more than 70 km ph. Took the car back and they said it is not their problem. Take it across the road to a mechanic. I phone more than 480min to the call centre and Al I get is they will get back to you. WE BUY CARS have the car and my money now for more than 3 week. Beg them for a answer to give my money back or fix the car. Just one guy try to calm me with EMPTY PROMISES. I lost a months interest on that money and struggled because I don't have a vehicle or MY MONEY to buy a new one.