Not answering does nothing to deter these vermin. Our answer machine kicks in on several of the same callers every day and we NEVER answer them. Get an answering machine and let it deal with them. Then you only answer calls you want.
I also block some through our cable company site. Trouble is, there is a 12 number max. Not NEARLY enough.
Got a call from a woman who spoke very poor English in a super fast Spanish accent saying I owed for a Sprint/Nextel bill. The first thing she asked was for the last 4 of my SS# and address. I didn't give her any information and she said they'd send me something in the mail and hung up real quick. I have never had sprint/Nextel service for anything!