Nothing works with these people, they swear at you or hang up on you when you ask the calls to stop.Now,whenever they phone,I just continue what I'm doing, but I press "1", and I will tie up the person on the other end for as long as I can string them along (can you imagine if this idea spread and one million people tied them up for 1/2 an hour, for nothing!)  Yes,I know it's passive-aggressive....