This is a number used by the Skype computer phone service. I know because I called my house to check my messages and this is the number it came in on. The calls you are getting are probably from other Skype users around the world either trying it out or simply making a missdialed call. In any case it is not a number you can call back.
If somebody is harassing you, then contact Skype at http://support.skype.com/en_US/support_request? and enter an abuse ticket.
here's the thing... This number 423-535-9357 shows on my caller ID as INTL. Number. However when I answer it is always my best friend who is calling from her home phone and doesn't even live in the 423 area code area. It never shows for anyone's elses number only hers and not every time. I'm so confused.. I have contacted my local phone company and she her's and no can seem to explain it.
I got the same thing this evening. A friend called me, showed up on the caller i.d. as intl. number. I answered it was my friend, and a very bad phone connection. She hung up, called back, 2nd time unknown caller. (and bad connection) 3rd time the intl. number and very bad connection. We couldn't talk long because of it, we could barely understand what the other was saying.
Over the past couple of months, have gotten several calls from this number and nothing is ever said--just a bad connection and buzzing sound in background
I have recieved MANY of these calls with no one on the other end...and also from 1-423-535-9564.. they are also calling my Cell and when I try to call them back it just says Network busy?!! or I just get a Busy signal..