Josh Chase at the Mercedes Swap Shop. He will need your car's ECU and SKREEM. There is almost no other alternative, many locksmiths will charge your a "trip charge to see what I can do", then bill you and tell you they can't help.
Same goes for dealers, the corporate channel from your dealer back to MB is gone, so there is no factory support.

Call Josh.

Click here:
https://themercedesswapshop.com/