Maybe the phone company can find out??? In the olden days if you called the operator immidiatly after a call they could find the number. With technoligy now I would hope they could. Good Luck I would think that is annoying. Maybe since it's a business phone you could say that "this facility does not accept collect calls"
Plus if it already paid for??? that wouldn't be collect. Sounds like one of those scames I heard about a while back...Then you get slammed with hundreds of dollers on your phone bill.
That is just one, it mentions businesses recieving these calls. I searched collect call scams. There are many. From prisons, and Mexico etc...
Reading through many of the phone scams...I found some phone companies offer free "Block third party" calls. After reading some horror stories of people getting bilked out of their money (even if your answering machine picks up) I'm going to call my phone provider and get the block.