Who called from 9515049741

I called back. After 3 seconds of silence, received the message "The number you have dialed is not in service. Please check the number and dial again."

Answered the phone, no one on the line.
I called back and number not in service! Who is this?

received many calls from this number and asking  for Michael Jackson or  Mrs Jackson

Have received several calls from this number with a woman asking for a Mr. Lee. Do not know the subject of the call.

Keep receiving calls from 951 504 9741 and sounds like call center, but never leave a msg and never speak. Prank Caller or ?