Great info from "Dandi" on December 23.  I can only add that the latest trend among these crooks is to hang up if your phone goes to voicemail.  I suppose they've found that leaving a message is not effective, so they just robodial again.  I always block the offending number, but I understand that it's easy for the scammer to "spoof" a new number.  I also report the robodial violation to the "Do Not Call Registry", but only once have I received any compensation.  A year or so ago I got a very small check from some settlement with one of the large scammers.  Now I understand that the crooks have moved offshore where they won't be prosecuted.   I think we're losing the battle and slipping into telephone anarchy.  Sigh....