Actually, there IS a bit of a "hack" to reach someone at a specific service center. Look up the number for the service center in question, call it, then listen VERY closely to the prompts. What you are listening for, is directions to check on the status of a vehicle currently in service.
That will actually ring the local service center, unless they have recently changed something. Ensure you already have a scheduled appointment when you do this, however, because when the human picks up they are going to want to look up your appointment.
Also explain to the human why you are actually calling, and needing a human (if you dont want to get rebuffed fairly quickly). Something like "I need to know an estimate of how long my service appointment will take, I am scheduled to drop it off on XXX day".
Not "I want to tell you about my battery degradation, my car is reporting 8 less miles than it used to".
Anyway... trying to check on status for a car in service rings your local service center, if you start off by calling them. Just about any other option routes you to a call center that is not your local service center.