Here's an idea: hang a modem on the line and let it answer. If it's a data call, it will pick up and squeal back: if it's fax, then it can be received and cleared. If it's voice, then eventually the noise will get someone's attention.

Why don't you post the number here and we will all dial it with re-tries every 30 seconds from our modems? THAT will wake the bugger up!