A few years ago I started getting faxes every 15 minutes. The problem was I didn't have a fax machine at that number so I couldn't read what they were sending.
After about 10 calls I got on FR and asked for help.
One of the better suggestions: get a piece of black paper and send it back to them. Do it about 20 times.
Or, send 20 pieces of black paper...20 times.