Trying to reset Service A9 indicator notifications after having had service performed.
When I have had similar problems I have phoned the place that did the service. They can usually walk you through the vehicle equivalent of “control-alt-delete” to reset the counter. Start there.
Utube has instructions
Do you still have the owner’s manual? If so, it might be in there. That’s where I found the service reminder reset procedure for my cars.
Mercedes does not include instructions in their manuals. Shops use a reset tool. Mercedes and BMW has an ignition on/off procedure to reset. You can find it on utube. It is tedious or you can take it back to your mechanic. I speak from experience with both vehicle makes.