Broke more than was fixed

I sent my car to Hyundai Menlyn's Service Centre for a 135000km service. They did all the normal servicing things but called me t say that my radiator cap is leaking and they would like to replace it. I told them I would replace it at a later time. After driving with the car the next day, my car started overheating and after popping the hood I noticed that there is no radiator cap. So they just took it....instead of a small amount of water leaking out, every time I drive, I need to fill up with 2L of water.<br> <br> My back window's electrical motor broke a while back after which they sealed the window so it's unable to open. After this service, the window just falls open, thus they somehow broke the seal that they have previously installed. I don't know whether they have done these things in order to lure me back there but needless to say that I will NEVER be using their services again.