Bad car service experience

Since my car service in november at Cartime Bellville, I had to take my car back twice, car wasn't clean when I received it back, carpets that fits under gearlever wasn't fitted back. This is minor compared to the fact that they worked on my breaks and skimmed the disks down too much, there is clear notice on disk indicating that the diak mustn't be skimmed thinner than 21 mm. Cartime phoned me and said my disks needed a skim. After service, there was a shudder whenever I braked, enquired about it and was told the brakes needs to be worn in as I also had brake pads replaced. It became worse, I took car back in and now I was told that my disks were skimmed to thin and I was given a quote for R3500 to replace the disks on the day they closed for christmas season. Why wasnt I informed that my disks were too thin for skimming and that disks needed replacing. I was driving around with disks skimmed down to 19mm which put my life in danger, my brakes could have failed due to heat generated from disk skimmed too thin. Bad service, money wasted on disk slimming and labour recommended by cartime which should've never been done in the first place