Need help

Hello to everyone here,anyone can give an advice with my problem. We rented an apartment which is an old one, with some one who's not suppose to re-rent this place.We really don't know this issue till the building owner knocking our door, and the best part is we have a 1 year contract with so called the owner. And now we want to cancel the check but the bank said we need to have a police report first, before we can do that. And when we went to the police station, they said we need to take back the check,but the problem the guy is not in Doha, so what we can do.Please help me........ thanks