Your problem is not mileage, but time. Your car needs regular servicing, regardless of how much it is driven. Your oil needs to be changed every three months or so, regardless of mileage.
That's why you mileage timer is not going off, but the clock timer is.
You should be aware you're not doing your car any favours by not driving it. Time is harder on cars than mileage, and many cars suffer terribly from sitting. I've seen more than a few old low mileage MB's turn into rolling junk when someone starts driving it. Seals and bushing are decayed, and oil that has gone unchanged has allowed internal engine corrosion.
Are you in the US? If so, why not take the car in? Isn't your service costs included?
1998 C230 "Black Betty"