Thanks Fallya, I think I will label mine too, tired of these bs calls from unknowns.  I don't answer them, but do look them up.  I did register all cell phones in the family on the National Do Not Call Registery www.donotcall.gov.  It has helped.

they Called, I didnt answer because I didnt recognize, looked it up online here and saw your post. Went back into my phones, cell/home, and named the contact " do not answer 5" (5 as I have other do not answers)

Also calling and hanging up as soon as I answer.... WTF?

these people keep calling and hanging up.