This number called my cell for the first time, just now. I didn't pick it as usual, since it's an unrecognized number. I was sure it's not worth my effort and 10 cents (my cell is a prepaid type).
Since the "Do Not Call" list doesn't seem to work and pressing 3 to opt out means nothing to these people, I have some fun at their expense. I Keep a recorder next to my phone and wait for a live person to ask me my name and blow until they hang up. I get my four children to make as much noise as they possibly can using very loud musical instruments, pots and pans, etc., and whenever we need to rest, I turn up the speakers with some ridiculous song from YouTube. This technique has dramatically reduced the number of calls I get.