Since I upgraded my iPhone 5 to iOS 7, Game Center has not worked properly. Game Center games do still work, I just cannot view what games I have or what games others have. I want to view my achievements for Tiny Tower but I can't; it says that there is no data available because of network connection problems or other errors. I know it isn't my network, and I haven't been able to figure out what's wrong. Any suggestions? I don't want to restore my phone.