I recently found out that my apartment is an illegal conversion and have been moving out because of it. It's been very inconvenient and difficult on short notice. I have a new place and am paying rent there, and moving my things out of the old apartment. I stopped paying rent at the old place and my landlord is trying to collect it from me even though he's been issued violation notices from the dept of buildings, and I don't even live there anymore. What should I do?

