Did the new tenants lease say that they needed to have the elect in their name? There is someone on charge of utilities. Like a regulatory agency. Hammer the utility harder. What does it mean that you transferred the account to the roommate. Like he was responsible, or just paying in your absence. I think they can write it off, you just have to be persistent. Get letter from landlord that you weren't living there then. Could you get the names of the tenants from other utility records? Ask your congressman for assistance?