BAD to horrible service

I am so disappointed with the bad service I continuously receive from Mercedes Bedfordview. Someone removed my navigation memory card from my GLC when it went there for service, for over a year now I have been fighting this and till now i have no solution. Then recently i took my car there for service ,and only at 4pm my car was being attended to ,when i never received any call during the day informing me of the service, when i spoke to the manager he left me there saying he is going to find out what happened and why the car was not attended to ,and he never came back. Such bad service over and over , for such 'luxurious' cars, I am really disappointed. I had to travel all the way to KZN with an unserviced car, putting my life and my families at risk for someone's inability to do their job properly or even offer me an alternative because they are the ones who didnt do their work. I am so disappointed.