Hey Xfinity, listen up!
You need to place a block on your equipment to reject calls that don't have a valid area code!
Yep, you have the resources and the ability to block tele-monsters that use invalid area codes.
Attached is one example of a tele-monster that calls every few weeks.
There are more that when one tries to look up the number on Google, it will not translate to a valid number.
(I didn't copy any of those.)
Think about it and get pro-active for your customers!