I hear you!! Just got our millionth call this month. When I press to speak to a rep, they hang up as soon as you tell them to take you off the list. How on earth do you stop jerks like this from harrassing you? We are on the NDNC list, but can't even complain if you don't know who is calling you!
By answering the call you let them know there is a person behind that number and you're phone number is now being sold to hundreds of telemarkting companies; it doesn't matter if you ask them to remove your number, they just sell it to someone else that you haven't asked to remove your number.
The only thing you can do now is change your number to an unlisted one and even that does not always work.