If that personâ€™s credit is bad (which it likely is) and they canâ€™t get credit, a phone, electric service or cable in their own name, thatâ€™s their issue to deal with; not yours. A weekâ€™s time is plenty of notice for them to take action. Tell them that if they donâ€™t handle it in a week, you will be forced to contact those creditors and utilities directly and advise them of the situation â€“ including divulging their identity. Hopefully, you will be stern and straightforward enough in your approach to this person that he/she will know that you mean business.
At this point, Iâ€™m still not saying that you have to turn the person in (although they do deserve it). But neither should you be held continually responsible for someone elseâ€™s financial mess.