This dealer service department are clueless about ...

This dealer service department are clueless about their cars. Brought the car once for electrical problem (car would not start, but started after disconnecting and reconnecting the battery) - they had no idea what was wrong.
Then there is a problem with break signal bulb housing (causing intermittent faulty bulb dash sign) - they cannot fix it, do random stuff instead. Once they replaced the license plate bulb, instead of break signal, claiming it was out (it surely was not - the dash signal only appeared after pressing break pedal). Next time they claimed I have wrong type of bulb and replaced the bulb - of course this did not fix anything, and the problem reappeared next day. I suspect it is a botched service of the housing (Mercedes Benz had a recall on it, which the dealer claims they performed).
On top of that they recommend random (different each time) services, with prices ~3-4 times above the average for the type of service.
The only part of the service they do right - wash your car, at least this part is fine every time, so I give them two stars rather than one.