It seems these people call every day.  I have pressed "9" as they instruct to add my number to their do not call list but it doesn't work.

Where's my gun???

They called but did not leave a message.  CallerID says "R Squared."  I did a search on the internet and found an "R Square" that is a staffing organization (i.e. temp jobs) and another for "R Squared consultants" that "provides pioneering solutions to educational/non-profit organizations and to small and mid-sized businesses."

My wife recently updated her resume on Monster, so I suspect this may be related.  The fact that they did not leave a message makes the call highly suspicious.  Unfortunately there are a number of sleazy organizations who troll Monster and other job/career websites for individuals looking for work in order to scam them.

We will see if they ever call back and leave any message.

Just blocked this unwanted calling jerk.
Because so many good folks telephones are being invaded with unwanted scam/spoof callers, several good folks and the Vonage VoIP Phone service, have setup a free call blocking service. On the Internet, Google  “free call blocking service” and see what is available, you will be glad you did. You can also get your own “Call Blocking Phone” and call-block all those unwanted callers. We laugh each time such calls ring our phone and are blocked and then exclaim, “Thank You.”

started today, some lowlife SOB cals and lets ring 4 times and hangs up

Called, didn't pick up ,they left no message. Caller ID says Clementon, NJ