Get a lawyer to help you. Legally, you cannot be held responsible for a bill, charges, obligations, etc. which you did not agree to and which someone put in your name without your permission. The fact that your ex-boyfriend was charged at least will help you--it is evidence supporting what happened. However, utilities and collections agencies can be very tenacious: let a lawyer help you straighten this out and get the charge out of your name, so you do not owe money and do not have your credit damaged. You may also wish to sue your ex-boyfriend for compensation, such as for the cost of your attorney.