It happens from several different numbers. However, I think the point is being lost here. If the phone is turned off or out of service area, shouldn’t it just go to voicemail? The automated "this number has not been assigned" message gives the caller...
I am having thie same problem. My wife is in Eurpoe, at the moment with her fido phne (pixel 2) and when I call her I get the number is not assigned mesage. Regardless of where she is, shouldnt it at least go staright to voicemail? Makes no sense. ...