Poor workmanship and poor customer satisfaction

please do not buy a car at VW Mastercars in Claremont they have the worst service ever. They sell people cars without having them check out as promised with there 50 or 60 point check. we bought a vehicle just under a year ago buy them via the salesman Garon. he advised us that the car has come in two days prior as atrade in and it needs to go through its checks before it can be placed on the floor. however we were told to put down a R1000 deposit to secure that we are 1st in line for the deal, this happened on a Saturday. on the Tuesday we received a call stating we have been approved for this Polo GTi. we then collected it on the Friday of the same week, we then noticed that the smash and grab tints was not done and the air filter box was not replaced, we were told to take the vehicle and that it would be collected again the following week. we then did so. That Saturday we had a battery problem of this vehicle same vehicle. the vehicle was then collected the Tuesday to have all these issues sorted. upon the return of the vehicle it was ok for only a few days we then noticed high oil consumption which was alarming. we then returned it to the deal and was informed that the vehicle is a high performance vehicle and that it will uses a lot of oil "Bull****" we were then told to monitor it and if it lessens we should bring it back. a few days later we required oil only after doing 700km. which again alarmed us we then took it back to the dealer who booked the car in. the car stayed for two days only to get a call that the number 3 piston was faulty or needed replacing. this after only having the car for 4months. this was replaced by VW and 3rd party. 6 months later we have a bearing knock on the same vehicle. apparently the pistons which they replaced 6 months early is also giving trouble. and there parts are guaranteed for 12 months. now VW Claremont is quoting us +-50 000 to fix a fault on a car that has not even done 80000km yet. do you think this is fair. how can a second hand car that was check by a dealer give you such problems in such a small space of time if the car was checked properly. I want to uplift this deal however the DP is refusing to get back to us. I feel we need compensation on this as this is a VW issue and not ours as the customer