Ex-spouse's heating bill

My ex-husband and I were divorced in 10/2009. He left the NJ property where both our names are on the deed on 12/2009 with a heating bill and is now residing overseas. I did not reside in the property since 2007. Am I liable for the bill even though it is stipulated in the divorce that he is responsible for all bills related to the property? I got a default judgment and I still have to confirm with the court if I was properly served because I never got a summons. I only received the information subpoena, nothing else.