Unrecognized--suspected spam--called the number back and, voila!, the old "line sits there dead for 20 sec. then a fast busy."  Bingo!  Another spoofed number.  Another new spammer.  I'd like to tell him to go to he** but I'd rather just let it roll to voice mail and frustrate him more.  Suggest you do the same.  Or don't even answer it.

Now I'm sure these are spammers--they called again the next day (1/26/17).  Of course there was no message left.

It was a renewalable energy marketing call

I stupidly answered, the person on the other end said something about "phone blast" and then hung up.  some people in this world are literally worthless.

They want to schedule an adviser to come out to your house to discuss solar panels.