Soledad,

It sounds like you've got the same kind of situation that I had. No amount of apologizing is going to do any good. It also sounds like she hates or is not very fond of cats.

People have to live their lives, and yes there is going to be noise, be it an accidentally banging of a door, something dropping on the floor, etc. That's to be expected. I'm wasn't about to walk on eggshells just to please this miserable person and neither should you. As far as the "contraband kitty", register her immediately.

I feel really bad for your situation and can relate to it. Maybe her lease will be up before yours and she'll move out.