Oh my gosh do you mean she lives upstairs and won't come down or go outside?? If so please tell me because I have a cat that does exactly that!!
My cat is exactly the same. Sigh!! I don't know her history as she was a stray from a rescue but she could well have come from a similar situation.
I've caught her coming down the stairs a couple of times but as soon as she hears a noise or sees you then she's back up!
Do you feed and keep her litter tray upstairs like me? :roll:
Yep!