I know that Facebook stopped letting users play through Google Chrome but still worked through other browsers, however you never said what the device type you play on is. It might help to know? But regardless let me suggest uninstalling the game completely, then go to windows store or apple or amazon and reinstall the game. Afterwards try getting into the game without Facebook, if it says register the name then do it and see what the result is( it might say already taken or it might go straight to your account or it might start fresh)IDK which. And double check your spelling, spaces, case, etc etc. Best I can do without actually having hands & eyes on device, hope it helps.