Sold a Defective vehicle as Brand New

I am convinced that I have been sold a defective car Polo Vivo 1.4 Concept Line by Market Square Dealer Uitenhage and their after sales service is pathetic even VW CIC customer care is even worse. I bought the car in 2016 November within the 1st 6 months of purchase it gave me problems with the sensor which I was promised it was fixed in my first encounter in March/April 2017. June 2018 same problem and the last straw was 2 April 2019 till today the car is still with them and no one bothers to contact me for feedback. VW refuses to account and pushing me to rather go for a trade in meaning I will start a new debt from scratch and whenever I contact them they promise to get back to me which they never do. All they care about is their image, brand and making profit and just simply don't care about the customer .I had high hopes after speaking to the principal dealer who promised to take care of my complaint but it's the same old story of promising without delivering on the promise. When I bought the brand new car from a dealer which I thought cared ,I wanted a peace of mind and not worry about breakdowns which turned out not to be case.I'm currently struggling to get to work and no body cares from VW I'm all by myself. All I want is for them to get me off that car's debt so I can go else where I DONT TRUST THEIR BRAND anymore.