Did Mercedes do the work or was it an independent shop, because, on this type of 2008 Mercedes, you need to REALLY know how to change the lighting system and be able to do a computer reprogram. If not, then I would go back to the person who did the work and say, 'fix it'
A 2008 Mercedes lighting system is run by a pretty hefty computer system and you can't just 'add on some new lights' with out the possibility of ruining some very sophisticated electronics. If the Technician does not know the Mercedes light system and does not have the correct computer to re-program the system, well the results will be any one's guess.