For the last two days, a fax machine has been calling our 800 number at work, and everytime we pick up the phone, we get that modem sound that pierces the ear. It would call every five minutes the last two days, today it's completely random and frequent. We tried hooking up a faxmachine to the line, but the fax won't go through. We tried calling the phone company to trap the line to trace the origin, but no luck. Any ideas?