Bad Service

I brought my car for service on the 1st June 2018 at Nissan Rustenburg. As part of this service I have also asked that you change my v-belt but surprisingly it has already worn out. Since the car went for service I have only driven 2 557km. I went back to the dealer and refused to replace it at their costs and as result I had to pay but they offered to put it for free. After they installed, I left the garage only to drive less than 10km and started to experience the same problem. I went back and they told me it was technician mistake. What was even worse was that No apology was given. I then asked that I get my refund because I clearly even in the first place it was their mistake of installing v belt wrongly. I was directed to speak to the service manager who refused to refund me even though the technician agreed to me that possibly this was the same problem. I am so disturbed by this and I dont think I will ever take my car there for service