Okay guys this is hilarious. I've thought hard about what has caused this and I think I have the answer.
You know Candy Crush, the game? It's a freemium puzzle game so whenever you lose you can either wait for 15-30 minutes (sometimes a whole day) or use real dollars to proceed. I quickly found out that instead of waiting you can just adjust the clock in the iPhone' settings.
I know I reached the end of August by using this trick so I must simply have reached August 29th, which is the expiry date of iOS7 beta 3. Hilarious and a bit sad. Haha
Downgrading to iOS6 now.
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So it seems that it did happen. Jikes. The servers were hacked. But it was not the cause for my problem.