[QUOTE=Raza]
Unsolicited commercial faxes from companies with whom you have no business relationship are prohibited by the Federal Telephone Consumer Protection Act (TCPA) [47 U.S.C. 227] .
The nice thing about this law is that you don’t need some Federal agency to enforce it; it empowers the victims to sue in state small claims courts, getting $500+ per infraction. Junkfax [dot] org and similar sites have details.
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And having dealt with the junk fax twits let me just add “Good luck getting anything but frustrated”.
To start with, they will lie. I guarantee that if you actually get to speak to someone and ask why they are sending you stuff they will claim that you requested it. When you inform them that you did no such thing, they will apologize for the “mistake”. Under no circumstances will they admit that they have done anything wrong.
This is assuming that you can ever speak to somebody, which they will go to great lengths to make impossible - the fax number will be a dummy (that’s illegal too) and the “Call this automated number to get off our list” will probably transfer to Canada (I’m not making this up) or some other location beyond US jurisdiction.
I went through this with fax.com - I had them dead to rights but they insisted that “someone” must have given them my fax number, and they wrote a confirmation letter to me stating that the “Customer who requested his number be used has now requested that he be taken off our list”. This is the type of shenanigans to expect.
FWIW I documented my experiences with fax.com and complained to the FCC. Shortly thereafter they got hit with a $5.4M fine for multiple violations of the TCPA. I can’t say it was my doing but I like to think I had a little hand in it 
Similarly with the telemarketers - for the record, I have it in writing from the FCC that the anti-telemarketing laws that apply to you the homeowner do NOT apply to your business. Roughly speaking, anyone can bombard you with phone calls offering toner or light bulbs or timeshares or whatever and as long as they are calling your business it’s extremely hard to get anything done.
I work at a big law firm and we started getting prerecorded calls from “Dorothy at the Mortgage Company” offering home refis. It took me a lot of time and effort but I was able to trace the numbers they used (despite things like them blocking caller ID), track down the small phone companies that “owned” those blocks of numbers and get the owners on the line. One guy was a blatant bullshitter (he was reviled online, other people had tracked him down and published all of this contact info, I think he was sick of hearing about Dorothy) but I kept after him. The other guy happened to be chief legal counsel for one of the telecoms; I politely explained the situation and he actually took action - checked on the offender, confirmed that their behavior was generating massive amounts of complaints and violating some kind of terms of service in their contract and had their phone contracts terminated.
“Dorothy” has pretty much vanished now.
So if you’ve got a lot of time and resources, and a very stubborn streak, you might be able to get something done.