You have no right to anything in there and they won't open it for you, because you did not lease the place. However, if she stopped paying, at some point, they will auction off the contents. Ask them when they will be auctioned off and keep tabs on the date. Show up and win the bid. However, when you are asking them whether they have determined an auction date, ask if you can pay what's owing and own the contents outright. Maybe you will get lucky.
Certified Paralegal, with 25+ years' experience.