Two things from my past are perhaps relevant here:

(1) I spent a difficult few weeks working as a telemarketer. Our instructions were that, if we got blown off (e.g. “No thanks, I’m not interested,” ), we should put the card with that number back in the stack, so someone would call them again in a couple weeks. If, on the other hand, someone said, “Don’t call this number again,” or “Take me off your list,” or anything else involving concrete instructions for the future, we were told to rip the card up and throw it in the trash, to make sure they never got another call from us.

Since then I always say, in a totally friendly voice, “Please take me off your list and don’t call again. Thanks a lot and have a good day.”

(2) Remember that book, “Life’s Little Instruction Book,” that was next to the till in every bookstore in America in like 1992? One piece of advice in that book was, “Never allow the telephone to interrupt an important moment. It’s there for your convenience, not your caller’s.” It totally changed my perspective, and now I answer the phone maybe 40% of the time.