Lack in serve, quality of service and overcharging

I took my car to Hyundai oudtshoorn for repair last year on the 8th of December 2015, I explained exactly what the problem was with my car, And asked them for a quote. They gave me a quote of R3144 with a discount, and told me that it is my cranck sensor. I gave the go a head to fix the car. I received a call on the 30th that my car is fixed. On the 31st I went to Cape Town driving the car for a week and the exact same problem occured. I had to tow the car from Cape town. The monday of 11January 2016 I called Hyundai workshop and told them what had happened, they said I must bring the car back. After a week they said its fixed again, on arrival I asked them what they have done, and they told me they just put contact spray and the car started, only to find while driving away for about 2km the same problem occured. I took it back same time. Yesterday 15 February 2016 I receive a call the car iz fixed I must collect it today, 16 February 2016, anx pay R3119.00. I haven't payed because I wasn't expecting a invoice as it should have been I come back. <br> <br> Need advice as to what is the way <br> forward, tried to come to and agreement, but nothing from their side.<br> <br> I would appreciate it if the m