Who called from 9712201926

Wondering who could this be, calling me from so far away?They call,let it ring a coupla times  and hang up leaving no message.

Called but wouldn't leave a message on answering machine..have no idea  who they are.

Called my cell phone. I don't know who this is and they didn't leave a message.

They keep calling, and my cell says there is a voice mail awaiting, however when I listen , there only dead-silence and a hang-up.

have called several times on my cell phone wehen I call back it says the line has been disconnected.