This worked for me. Log out of your game on your device. Now Google Facebook and click the link. It should open in the other persons account. Go into their Facebook and log them out. You should now be able to log yourself back into Facebook using the account linked to your game.
I had the same problem but have solved it. You have to log out of the other persons Facebook account on your device. Log out of the game and close it. Google Facebook and click the link. It will open with the other persons account. Go into their Facebook and log them out. You should now be able to log in using your…