When that did not work, despite being put on the 'no call list', we just quit answering.
My problem is these people would never stop calling, ever. Like "The Terminator", it's what they do - it's all they do. The calling is automated so that a machine calls your number over and over and over (daily, not every five minutes) until it gets a live person. It can even discriminate whether it gets an answering machine or a live person.
I left a NASTY message on my machine until I figured out that it was being delivered to a machine. So you can not answer, but you still get five or six calls a day, all hang ups. I'm not a patient man - this tended to provoke me to violence, except the object of my rage is unavailable to express my unhappiness. That's when I started picking up the phone and telling them to leave me ALONE. That's worked fairly well, except that new charities still get my number and call, so I have to put a stop to them as well every now and then.
Oh, thank God your a charity, I just lost my job, my wife is sick and my dog too. How do I apply for money from you?
Hello? Hello?
At that point I set the phone down, line open, and go back to watching "Green Acres."