Modern technology has given telescammers the tools to call you.
Since those telescammers are criminals, they ignore both the Do Not Call list and any request you might make.
Modern technology can also protect you, if YOU do a few simple things!
The most effective thing to do is to get a call blocker device, service or app.
Then, use it correctly.

Google "call blocker" for more information, or visit Amazon or similar sales site.

If you cannot afford or use such a tool, then:
* Do not answer calls from unknown numbers ... let them go to voicemail or answering service
* Do NOT return calls from unknown numbers!  All that does is verify your phone number!  And, in some cases, those return calls may cost $20 or more to complete.  
http://www.forbes.com/sites/josephsteinberg/2 ... des-its-a-scam/
* If you have a "dumb" cell phone, assign the scammer's number to a group named "scammers" (or similar).  Then, assign a silent ringtone to that group.

_/