Who called from 2135371383

Called me, and left no voice message. I tried to call the number back, and all I got was a busy tone.

Got repeated calls from this number, I never answer, they never leave a message. Something strange I noticed, the number disappears from my caller ID after a day or two.

We are getting these calls into our office and the receptionist is out.  We've blocked the number on our phone system, they have gotten a little too aggressive and are not taking "no" for an answer.  We have had some fun w/ distracting them w/ bizarre conversations

This number calls and doesn't leave a message, but even the one time I picked up there was no one talking so I hung up.

Called me at work at 9:00am.  No message was left. Tried calling back and there was a busy tone.