I get a call from the same fax number almost every day and am getting fed up with it, I have tried to call the number back but of course it is no use, this is crazy, how can we stop

I consistently receive faxes from a company called 3W Group. I am on the donot call registry but that does not seem to deter them at all. I would like them to stop. I don't have a fax machine anyway but they keep calling.

A fax call to my land line
Caller ID: 3W Group
Caller: 3W Group
Caller Type: Fax Machine

A fax call to my land line