I just got this and I got a call from 312/878-9583 the other day, twice. My mistake was siging up with a web search required me to include my cellphone number. so, now my cellphone is listed and available via the web, just like in a phone book.
For those receiving unwanted calls.
Go to https://www.donotcall.gov/default.aspx
This is a government page, where you register up to 3 numbers (at a time) and you opt out of receiving marketing or unwanted calls. I have registered phone numbers before and it does work.
I recently added a Google phone numbers to my Gmail account and I was receiving calls from these people.
I registered my Google number hoping not to receive any unwanted calls.