Google and Facebook were blameless. It was the nut behind the wheel. The idea came out of nowhere, so I give the Lord the credit and praise. Facebook messages hadn't been arriving on my Google email. I learned that the problem originated January 16. No fb messages until this week.
I enquired of facebook friends and checked many settings, to little avail. Then, one day the epiphany happened.
Don't be paranoid as I had been for over two weeks. If all of a sudden, usual friends' mail to you stops, just don't assume that the friend or friends dropped you. It could be a user error.
On Gmail at the top left are side-by-side buttons for Archive, Report Spam, and Delete. I save some messages after I read them, but I delete most of them. On Jan. 16, I "deleted" two facebook messages, but the hand and mouse clicked the wrong button, Report Spam.
Hardly ever does one look inside the spam box, but I was led to do that, and, behold, my incoming facebook messages were there. Took a while just to return all them to the inbox, and I'm still catching up.
TIP: Check your spam every month to make sure you haven't accidentally spammed an email friend.
William A. Ricks