Instead of unleashing your fury at these callers, try a different tactic. You see, these telemarketers have a screen and they make rapid call after call. When they speak to a caller on a tirade, they just click on their screen to the next caller and therefore, your name is still on their freaking list. So when they call next time, try to talking to them politely and explain to them that you have notified them to the do not call list and that you(telemarketer) is on record of not complying if they don't delete your name from their system. I did this and I am no longer getting calls from them.
I heard a recording from a guy who had a setup in his bathroom. He took the call, then said something like "Hang onasec, I gotta go wiz really bad." And he had gallons and gallons of water set up to sound like he was pissing up a storm for as long as he could keep the guy on the line. He says to the telemarketer stuff like "We can talk when I'm done - I don't think well while I'm doing this." Eventually the telemarketer said he'd call back.