Here's what we do:
(1) Say, "Oh, yeah, hold on a minute" then set the phone down and play obnoxious music until they hang up.
(2) Say, "Um, you just called me yesterday and I signed up. What? You have no record of that? What kind of company are you? I'm notifying my credit card company right now!"
(3) Say, "I'd love to do that, but I don't believe in it (whatever it is -- cell phones, having your web site upgraded, satellite TV -- whatever it is, I claim not to believe that the technology is possible, that no one has proven it to me scientifically, and I have yet to have anyone try to explain to me exactly how "voices can travel over the air without a line, like traditional phones.")
(4) Say, "I have to check with my cat. You have to understand, my cat is a Methodist." (This answer isn't meant to be offensive to Methodists. It's meant to make a statement so illogical, there's no way to respond to it logically. Anything along these lines will do. "The voices told me to consult the Great Pumpkin before I make any commitments." "The nearest fire hydrant to my house is a half-block away and I have to move the light post before I can do anything else.")
The important thing is to have fun.
-Dorothy (LadyZolt)