I used to be really bent when telemarketers called. I got over it using this tried and true formula.
Oh, its fun too!
Phone person (PP): "Hello Sir we are conducting a survey in your area and would like to ask you a few questions."
Me: I would be more than happy to do so, what is the remuneration for my information (you must say this really, really happy like to be totally effective)?
PP: "This will not take long, etc."
Me: Well you are getting paid to work the phone, your company is going to sell this information to someone or you would not be at that phone. I am willing to supply my information, how much are you going to pay me for it? *blink, blink*, smiling.
To be totally effective at this again, this must be said in the most cheerful happy voice you have. I don't have much of one, but the results are worth it.
PP: (Brain vapor lock has occurred) "Thank you for your time Sir".
Me: Have a nice day!
What's fun is to see how long they want to play the game!