They left no message. My # is also on Do Not Call Registry, but I now know that it is niaive to believe that system has any teeth to do anything about nuisance calls. I don't know what's worse; getting the calls or having to see an inappropriate ad for "NaughtyDate" on 800notes.com while trying to add my comments.
I just got s call from this area code. I get spam calls all day..if I don't know the number, I just ignore. Seems the only easy solution. If the number is not familiar, don't pick up - ever!