Return of vehicle

On the 22nd of June 2017 i bought a car at Mega auto Motors in Boksburg, they were very helpful in helping me pursing the car, and they showed me a few faults on the car( rims have marks and bumper have a few marks) i was fine with that. while test driving the car a engine warning light showed and they told me that the car just came from a service and that they will reset it. i took the car and believe them what they told me, on my way home the engine light came on again, the following day when i was driving i put on the air-con and it wasn't working and the car started to leak oil badly i phone Mega Auto Motors and they told me that i must take the car to Steve's Auto Clinc, i took the car to them and the sorted out the oil leak but never the air-con, i phone the dealer and he told me that the repair for the air-con was to expensive and that he can fix it for much cheaper, after i received my car back from Steve's Auto Clinc my car didn't have power and there was a noise in the engine, i took the car back and they replaced the vacuum pipes on the car after waiting again 2 weeks for the car i received it back i drove the car a few days the engine light showed again and the noise in the engine was getting worse, i took it back to Steve Auto Clinc after phoning Mega Auto motors, Steve's auto clinc phoned me back after the car had been standing there for more than a week, and told me that they are not going to fix the car anymore and that i should come fetch the car,they also told me that one of the rims was patch with glu and that my engine is not right and that it is going to break down,and that my spare wheel didn't fit on the car, i Phone Mega Auto Motors again and they told me that they will fetch the car and that they will fix the noise in the engine and sort out the air-con, i waited again a week when Derick at Mega Auto Motors phoned me and told me that the car was fixed and that they will bring the car to me, after a struggle they phoned me and told me that they can't bring the car to me they can only do so the following day, but i couldn't wait the following day because i already arrange to be at work the following they, i got a lift to Boksburg and fetch the car, the following day on my way to work the turbo broke, it was white smoke coming out of the exhaust, i phoned Mega auto motors again and the fetch the car, after another week of standing they replaced the turbo and told me that the air-con work, i received the car back and it seems fine, after i switch the air-con on it wasn't making cold, i took the car to a RMI service center and they showed me that one of the pipes burst, they replaced it and i called Derick again and sent him the invoice, he told me that he will refund me but im still waiting for the money. i email Herman Vrey on the 6, 8,12 and 21 September and i have no response,after all this this is now 26 of September 2017, the car was in and out of the garage for repairs, i need a reliable car to get to work as im having a lift club as well, on Wednesday 20th September 2017 i was on my way to Alberton after work the car started to shake and jerking allot and then the engine light came on and the car cut out, the car left me on the side of the road at 8 in the evening, after struggling to get the car going again it stared and i drove to Alberton, the following day i drove back and it started to cut out again, and then after a while its staring again, on Friday 22nd September i phoned Derick and his phone was off i phoned the office and they told me that he was out, up till now he hasn't phoned me back or tried to make contact with me. my question is can i reverse the transaction or swap the car for another car with the same model and same price range, because i need a reliable car to get to work and back.I can't drive a car that is breaking down every time, from the day i pursed the car it was in and out in the garages for almost 4 months now, the longest that i drove the car was now 3 weeks and then i cut out. Im now really sick of this car im to scared to drive it because it will break down.