*********** staff and poor service

I took my car for service on the 14th of Dec 15 and was told my car had passed the service plan it was initially covered for. I was told it was covered until 90 000km whereas on my contract it stipulated up to 120 000km. They insisted I pay cash for the service of which I did and told them I would provide them the following day with the copy of the contract. They said they would gladly refund my cash payment. The documents were provided as promised. The same week the car started to have unusual sounds and brought back to them on Friday the 18th, Quinten fed me some story of what wrong with it and that I needed to book it in to have it checked properly. On Monday the 21st the car was checked only to find that the brake pads were finished and had to be replaced even though the car was there for service the previous Monday, somehow they failed to pick it up. The same week the brake pads have been replaced the car is making squeaky sounds when I apply the brakes, honestly what was replaced? please let me know, now I have to bring in the car to be checked for the 4th time in 3 weeks, what is it that you are servicing? And to this day still haven't received my refund