Help Having trouble connecting games to Facebook account on Android S3

[Yu Tan]

So there are a few games where you can connect to Facebook, but it doesn't work for me.
In one game, Songpop, I'm given the option to login to my FB account, and after I fill in the details, I get a black screen and have to reload the app. The app is sending me notifications of people I'm playing in the game, which are related to my acc, but I when I click on the notifications, the app says I haven't logged in yet.
In another game, Candy Crush, when I try to connect the app crashes and reloads itself without having connected.

I don't know how to solve the issue. I've tried reinstalling the games and also FB app, but it doesn't work. I'm thinking there are some hidden data files with my acc somewhere in the Android files but I don't know where to look.

I'll appreciate any help.
And no, resetting to factory settings is out question for now.

EDIT: it worked fine before, and the errors probably started when I tried switching accounts.

 

[Pugs1957]

Reading your EDIT, I think your only option is a reset.

 

[Yu Tan]

okay, then maybe anyone knows a way how to save app data?
some apps in my phone aren't linked to any accounts and I might lose the data on them

 

[Pugs1957]

You could try Helium Backup but I have a feeling your app data may be corrupt because of the second account which is why you have the current problems.