These guys are persistent and if you answer them they just call more. Typically this is call spoofing, where information phishers pose as information collectors to gain private information about you using false numbers. The do not call list and better business bureau can't help because you don't actually have the number of the caller (usually it's an Internet call running through a proxy analogous to a VPN).
If you're on a cell phone here is what you do. Download a ringtone that is just silence. They're free and can be found on google quickly. Then make a contact for the caller on your phone, and set their ringtone to silent. They'll call forever, but you'll never have to listen.
I hate answering a call to find dead air at the other end. At least give me a live person so I can tell them not to call again. Since I have my resume out in circulation, I've been answering caller IDs that I don't recognize, something I rarely do.
Well, what do you make of this?? 657-269-7794 showed on my Caller ID as Wireless Caller.
I decided to call the number back and got an interesting recorded message with a man's voice saying something like, "If you received a call from this number please do not accept any further calls. This has been identified as a scam to get credit card and other personal information. Do not accept any further calls from this number and do not give out personal information over the phone."
Then the phone company recording (woman's voice) saying, "This subscriber can no longer accept calls."