I'm also on the do-not-call list and get daily calls from these spammers and/or others. They generally off-shore using computer software to dial many, many calls a day.
Call comes in as Native American and says they want to install a free security system from GE in your home. I have pressed 2 to remove my name as instructed. I have talked to a rep about getting my name removed. Today, I got two calls from them after I pressed 2 the first time. Asked this rep how I get my name off their calling list and he said when I get a system from them!!!! Asked if their policy was to harrass people, he said they were not harrassing, they are just persistent. When I asked if they had a system that would stop them from calling me, he said he would pray for me.
Although caller ID identified differently this time (as Native American) it is the same recorded message I have got before. It starts out in a demanding voice "Don't Hang Up" but that's what I did immediately. I know from previous calls they are offering me a "free" alarm system which I don't need--already have one. (I wouldn't take it from them even if I didn't already have one). I don't know how they get by with this. Have been on Do Not Call list for a long time, but somehow the sleaze balls slide through anyway.