First, I am registered on the No call list. Second, if one does call, I tell them that, and tell them they are committing a felony, and if they call back I will report them. (I don't know if that is true about committing a felony or not, but I usually hear a click by the time I finish the sentence.) If all else fails, I just don't say a word, just hang up. Good Luck!
Oh, I used to feel rude not listening to them, but after all it is my telephone, I am paying the bill, and it is not their right to disturb me. You wouldn't let them in your house would you?