I got a call from 385-945-9647 on April 24, 2017 at 11:03 am.  The caller left a partial message about getting a "personal medical alert system," whatever that is.  My caller ID said, "Invalid Number."  What legitimate company uses invalid number as their caller ID?  Don't all legitimate firms use their real name for their ID?  I would think so.  How many people would pick up their phone when their ID says invalid number?  Probably not very many.  I have been on the federal Do Not Call list for over ten years.  I will report this call on donotcall.gov.