disgusting repair service

i took my car to mercedes benz dealer in sandton january to get my car sunroof fixed as it was delaying to close at time not close at all.it only worked for a month same problem started again but now it would open everytime im out of the car after locking and not close at all,when i took it back they demanded i pay R22,500 for the damage they obviously never fixed in first place..i would never recommend any family or friend to use that dealer they obviously dont know what they doing