I remember I had a Mercedes and I got a letter from them offering to fit the "My Mercedes" hardware for free to my car which would link into my phone. It also gave them a way of telling me to come in for an extortionately prices services.
I booked in, turned up and waited for 3 hours while it was in the workshop. I was fed nice coffee and posh biscuits while I waited. At the end of it, a young lady came out and sat down and talked me through the full inspection that they'd carried out (all free) including updating the software, topping up the levels and replacing a clip that was a factory recall.
"Great" I said, "Now how does this My Mercedes thing work then"
"Oh" she said "We haven't got any in, you'll have to come back for that"
I never returned ... although the biscuits and coffee were quite nice.