It's entirely possible the number you quoted belongs to some innocent person and is just being used to give out to prospects who ask too many questions. It would not surprise me if these people figured out how to fake out caller-id.
I agree with the frustration of constant sales calls, but we don't want innocent people to get harassed in the process of fighting back.
There was a letter published in the newspaper complaining about all the soliciting calls from politicians, which are exempt from all the rules. I've already been honored by calls from the President, past president, governor, senators, etc., except all were recordings. One call was from a real person volunteer working locally in a campaign whom I think actually dialed the call herself, not using a machine, but those are rare.
Many unscrupulous companies make sales calls or unsolicited faxes knowing it's too hard for ordinary consumers to fight back. (I don't know the law on faxes, but we get lots of scam faxes; we just thrown them out but it irks me since its our paper/toner being wasted.)
Unsolicited faxes should be illegal. No "one time" exception, no excuses. Telemarketing, including political calls and charity calls should be illegal.