I feel sorry for telemarketers. I'm sure they must be saddened by all the hangups and irritation they encounter and I figure they might be pretty desperate for money.
I have developed a polite, but firm answer that I give the moment I reaize I have answered a telemarketing call.
I say, "I do not purchase anything offered in unsolicited telephone calls. And I do not participate in surveys or contribute to charities over the phone. Thank you for calling."

Then without allowing them a word, I hang up. Almost always as I'm hanging up, they are thanking me. ??
smile