Called my Google Voice #. No CallerID.
I didn't recognize the number, so I didn't answer.
Left no message either.

First question: IF you did not recognize the number then why did you answer the phone?   When you do all you have done is to confirm for them that your number is a viable, working number and they WILL  continue to call you, plus sell your number to other scumbags.   Thought for the day:  What IF NO ONE answered their calls?  Would they finally have to give up and go out of business?   Hope so.  PS/ our government's DO NOT CALL list is a joke too.  It works no better than our government does.  Have a great day.