This number seems to be associated by various reports with a group or person whose purposes seem bizarre or perhaps downright nefarious.  They seem to be operating at the fringes of the law.  One report lists it as a debt collector using a variety of  720-763-xxxx digits.  Others claim silence or very abusive treatment with no apparent reason or direction.

Answered call and recorded message says "hold for a very important message." Calls several time a day. Spam!!

This # has called me repeatedly, never leaves a message so no idea who they are but if they were legit I would imagine they would leave a voice mail since they call me so often. Pretty sure they are some kind of scammers.

I just called this # to see who it was, this is Trans World Systems, they are a notoriously horrid and unethical collections agency.  Never answer calls from them!!