Who called from 2015704824

calls my fax line multiple times daily

caller didn't speak and disconnected after a few seconds.  I called back and got the msg that the number is not in service.   Looks like a fake caller-id posing for robo-prescreening call of some kind.  Maybe preparing for a scam in the worst case.

It's called "disposable" number. It's being used outside the USA

This call came on my Verizon cell phone,  the call disconnected. Have now blocked the caller.

Called and no answer. I called back and the number that called me  supposedly is out of service. It is just their own recording of that message and the number is actually working, but they don't answer because they are just finding out who is at home and who is not?