Are there any Acura Service Department Managers out there?

[LA Boston Gal]

I took my 2008 RL into the Acura dealer for its "scheduled maintenance" only has 24k miles on it but for some reason B12 light was on. Service dept said I drive my car too hard because the B12 only comes on at 30k miles or harsh driving conditions. Well, I hardly drive the car and I certainly do not drive extreme. Anyway, car was done the same day. I picked it up the next morning and drove 4 miles when the "check sh-awd" light came on. I took the car back to the dealer and it has been a week they've had my car and they still don't know what the problem is. Computer was changed now the rear differential is being changed. What happens if they can't fix the car? How long do I have to wait? (They're providing me a loaner) They still don't know what the problem is - so they're just doing trial and error replacements. This has got to be costing Acura a FORTUNE. When is enough enough and what kind of options does Acura offer owners if the problem cannot be corrected?