I suspected this would happen to us, but it still hurts a bit. Late last month we got the cell phone plan finally split so that the other people that had phones have taken over their portion of the plan. There was an amount due last month for September's service and then we got the final bill with October's service that covers up to the end of us being together. The way it had been working was we would send them a text message at the beginning of the month with their share and they would pay by the end of the month or the cell phones would get disconnected (we were always a month behind).
Without the threat of being shutoff (because my wife and I paid the past due and their phones are no longer on our plan), the 3 adults (in the age sense) that have the other phones did not pay at the end of last month, we sent them another text message a week ago and they haven't responded one way or the other. We have decided to pay it all and just consider it our act of service to God. If they pay it, great, if not, we are at least free from being chained to them.