The best way to mess with these people is tell them you'll donate so have them send you a bill then send it back with no money and write on the bill to take you off their list. They get no money and it cost them postage.
Called and I answered "Hello" in an annoyed manner, expecting a telemarketer. The man said, "Dam- fool!" and slammed his phone down. It was unnerving to read these other replies.
Called twice with hang-ups both times, then called a third time, but I didn't answer--they didn't leave a message. Same people called me a couple of years ago asking for a donation. When I told them that we prefer to donate to charities of our choosing and that our budget was a little tight at that time (which it was and still is), the guy on the other end yelled at me saying, "What, you can't even give $10?!!!" Very rude man, so I hung up. If they are so rude to everyone, and they are written up to be a scam by news organizations, then why haven't they been investigated and disbanded by now?