Called 4 times in 90 minutes, starting at 8:12 am. Due to "unavailable" and just a number on caller ID, I did not answer. Upon investigation here and using my phone app (HIYA) I discovered that it is the 'virus on your computer' scam. Since I have a service that allows various ways to block, they are now going to receive the This number has been disconnected or no longer in service message.
United States