I got this call, too. My cell company blocks numbers when I request it. I just remembered that! I'm also getting calls from the 616 area code so I'm off to block both!
We have been getting daily calls from 830-432-6874. It comes up on our caller ID but when I use a REVERSE PHONE LOOKUP service it says that number is not a valid number.
These services didn't work with this number but they are useful to keep:
USE A WEB BROWSER TO TRACK A NUMBER:
Write down the unidentified long distance phone number. Enter the number into a search engine search box. Often this will lead directly to the person that called or give the company name of the caller.