I won't answer if the Caller ID reads "Unavailable," and I don't recognize the area code.  No message left.

I am also on the DNC list, but every time I try to get some info to get them stopped, they hang up.

This time, I played along.  The automated message said they were from "Credit Card Services".  When I spoke to a representative, he asked if I wanted to lower my credit card rate.  I told him I did.  He asked if I had over $4000 in credit card debt, I told him I did. (even though I have no credit card debt.)  I was trying to get to the point where he would ask me personal information so I could question him back.  

But then the curious question happened:  "Are you over 70 years old?"
I replied no, thinking a credit card company would be interested in younger people.  With that, he hung up.  

It concerns me that they are targeting older people exclusively.  My grandparents would probably fall for this-

cALLS ABOUT ONCE A WEEK -LEAVES NO MESSAGE-CALLS AT VARIOUS TIMES IN THE EVENING AND LATE AFTERNOON. HAVE BEEN GETTING THESE ONTARIO CALLS FOR AT LEAST A YEAR NOW

I don't answer calls from numbers I don't know, I am also on the "Do Not Call' list.

I picked this call up by accident, as I was expecting someone to call.  When I just heard dead silence on the other line, I checked my caller ID and realized it was a dumb telemarketer.