Overcharged by VW and unfair threatment

I bought car at VW Centurion In 2018 and car was added warranty on it and it stacked with a month after I bought it in 2018 and VW checked it the was any faulty found and it stacked again at same day after fetch it at VW Centurion and after they took it for a week to check it after they didn’t any faulty again and I asked them to change a car and refused , I continued with it in six month it stacked again for third time and contacted VW Centurion to take their car back and they still refused to change it and exchange it for I paid on the side amount of R24000 to fix it and I asked for detailed statement this I found out that I’m paying warranty for R500 the one the refused to fix my car and contacted them ask for refund from beginning till to-date and they refused it cost R25000 till to-date and in future to pay amount installment of R3500 till end of contract and still they refused I want warm people to be aware of such things I had when other clients complaining about things like this I wish to reverse that amount from my Installment at Bank