Fake number - comes up as changed, disconnected or no longer in service. Safe to assume this is a robo calling telemarketer using fake numbers or spoofing software.
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 first thing to do is buy a call blocker device, service or app.
Then, use it correctly.
Google "call blocker" for more information.
http://goo.gl/cdPm8O
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.
* 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.