Follow these simple steps:
-Put Landline and Cell on Unlisted
-Only give Landline and Cell to trusted People (Like Family, Friends, Doctor, ect...)
-Get Google Voice Number
-Give Google Voice Number to Everyone else
-When you get Telemarketer Call, hang-up, go to GVoice App or Site, and Block their Number
Now whenever they Call you again they get "We're Sorry, You have Reached a Number that has been Disconnected or is No Longer in Service..........
Basically making them think you changed your Number. Even if they realize what you did there's nothing they can do, except use a different number(happened once to me) but you can just block that one too!
Now, Enjoy the Feeling of Pure Power and Control :)