Raceview sold me a voetstoets

I bought a vw golf 6 gti at raceview and from a salesperson named Leslie on the 17th of march, i returned the car after 7days because the engine light and the epc light came on, they couldn't fix the car and Leslie told me to leave it at the recon department for a week, i did so and fetched it after a week. I drove the car for two weeks then the problem returned again. Since then they have been failing to fix the problem. Even the dealer principal made empty promises even now. I drive the car for few days and i take it back to the dealership every month. Cecilia who is the dealer principal also failed a multiple times to fix the problem, the car even cuts at a stop. I also spoke to Charles the sales manager but nothing helps. Ever since i bought the car i haven't spent at least 30 full days with the car but its been 38 days with them at the dealership now and i am paying the bank every month. They telling me that they cant exchange the car for another one now because the bank does not approve. I need help even my health is deteriorating due to stress every day for paying for a voetstoets car. But the slogen on the dealership says quality pre owned vehicles. I dont think so. They sell voetstoets