How do I get a deadbeat landlord to pay the penalty for backing out of a lease at the last minute?

I signed a lease with a landlord who backed out of the agreement just before my move-in date. My deposit was returned within two weeks, but he has refused to pay the penalty fee that is stipulated in the lease agreement (either party is responsible for 2 months rent in order to break the lease). This lease was handled by a third-party property manager, which complicates the situation a bit. The landlord has been sent to collections but has still not paid after 8 months. How do I proceed?