Called three days in a row, and left a message about how I could get a free alarm system by merely putting their sign in my yard. Comes in on Caller ID as "VO I P" which means "voice over IP", a type of inexpensive phone service.
Caller ID read VO IP. Robocall started with "Hi this is Heather. You have been selected to receive a free home wireless alarm system. This is obviously a criminal scam as I'm on the "Do Not Call" list.