Game won't let me back up data please help (darksword)

I only ever managed to back up my data once back when I was only lvl 9. I am now lvl 42,and have acquired good gear and do not want to loose my progress. Every time I back up it either says unknown error saving progress or, it says in use on another device. I have since uninstalled the game ( darksword) on my tablet but still says its in use on another device. I don't understand why the game is set like this and doesn't just automatically save account data. I hope someone can help. Cheers, Jonathan