I would call and speak to a customer service SUPERVISOR. Your friend knew the service was supposed to end, and used the phone to call out of the country anyway. He/she is responsible for those charges, but if you get a sympathetic customer service rep, and plead your case without screams and rants, you may just be able to get them to wipe out the bill entirely, or at least cut it way down. Most companies will forgive those types of charges if you call and speak nicely, and ask.