Called (only once - shockingly) - left no message - when I called the number back (hours later - same day) I received a recording telling me "...the number you have dialed is not a working number...please check the number and dial again..."
so that usually means, TELEMARKETER, AUTO-DIALER or some other type of scam!
Ignored call. Called it back after business hours. All it said was DIE ... and hung up. I thought I heard wrong ... so I repeated 7 times. All of them the same ... DIE ...