A call to Mercedes will get you an answer, on exactly what documentation is needed, such as receipts for oil and filters.
I can't answer your resetting question, for Mercedes, but my Toyota has a service reminder that shows up on the instruments. I have two trip odometers, "A" and "B". After I change the oil, I reset the "A" trip odo to "00000" per the manual instructions, and the reminder resets for another 5000 miles. It's probably not much help on yours, sorry.
Every day's a learning experience, though sometimes not what we expected.
2012 Jay Flight 19RD
2016 Ford F150 XLT 2X4 SC 3.5L Eco Max Tow
2010 Tundra TRD DBL Cab (Traded)
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