Ford fiesta st

I bought a car from auto nantes paarl in July and I had car 2 weeks and it gave error message saying engine malfunction sent it back to the dealer at my own expense costed me R850 car came back fine few days later same thing all together car was sent away 8 times from Mitchell's plain to Paarl and still not fixed today I'm sitting with a vehicle that's broken and its not even 6 months and salesman started to get frustrated and accused me of racing with the car how do I get my money back or car fixed , i have all emails and chats with Tiaan the salesman who sold me a defective vehicle , I was ripped off and robbed each month that debit order goes off I am disgusted that people can do something like that for a sale and always replacing small things but ford said it was its turbo but salesman who knows nothing about mechanical things tells me it isnt