User blog:Spenzir/iOS app help!

I can't play SAS 4 on my ipod 5 anymore. It started with me purchasing something in the store and it was taking a while so i shut the app down (by doubleclicking home and swiping up). Now whenever I open it, it crashes. I tried shutting my ipod off, redownloading, hard restart (holding the power and home buttons). And when I install using itunes on my computer it doesnt crash but it just shows a black screen and plays the music in the background. I assume its because I somehow corrupted my data. Deleting my data from the game center might solve that but I'll lose my level 51 assault character. What can I do please help ;_;