Who called from 2108923527

Got a call and answered it against my better judgment. Got a robot voice saying "hello? hello?"

Plz do not call my phone if not going to leave a message or aws my calls

Called an unlisted number. I did not answer. I called it back and it rang and rang then it hung up

It has does not ring when I call it back.  I think someone is trying to find my location

Just called me now 1:10PM 12/23. I didnt answer, no message