Unknown, call came to my USA cell phone and no message left. I checked on line and found others who claim this is "Identity Theft", dialed from "Blyth", when asked to leave a message the caller hung up and was said to be sounded like a Hispanic woman.
On my iPhone I have a contact named "Do Not Answer". When I get these types of calls, I immediately add that number to this particular contact so if and when I get a return call, it shows as "Do Not Answer", so I ignore the call. I thought this might help some of you who have this capability on your phones. Good Luck.