My girlfriend and I moved into an apartment in California with a roommate and signed a lease for a period of one year. The lease only converts to a month-to-month lease after the 1 year term has ended. Four months into the lease our roommate informs us that he has purchased a plane ticket back to NY and will be leaving in two weeks. To my knowledge, the roommate never informed the owner of this, but shortly after we were informed the roommate was leaving I did ask the building manager what to do about securing a new roommate and what paperwork would need to be taken care of for a new roommate to move in as we wanted to remain in the apartment. Two weeks later the roommate was gone, after having tried to skip out on rent for the final month he was there (rent is due on the 1st and he moved out on the 4th) and leaving a mess for us to clean up, no less. We had told him that we would refund his security deposit when a new roommate moved in and paid his or her own security deposit. He decided that we should keep it and put it towards the $700+ he still owed for his share of moving expenses that were never paid. It is now coming up on the due date for the next month’s rent and we do not have the funds to cover his share. What, if any, options do we have to collect payment for his share of the rent as per the lease agreement he signed?