You say she owes you money, did you and her co-sign some kind of lease agreement?
Also do you both have any mutual friends that you could use to get this furniture thing resolved? Basically if you sell the furniture without her permission it could come back to haunt you.
I've been where you are and trust me the best thing to do is to act like a responsible adult and not try to do anything childish or underhanded to get back at her. Basically keep everything above board and just move on. She's not worth the amount of time you're spending thinking about her.







