the exact message is - after entering apps store p/w and confirming purchase "this in-app purchase has already been bought. It will be restored for free" candy crush then hangs so I have to swipe to kill the app. As I said restarting/clearing the cache makes no difference.
As I said this started happening last year so obviously I have restarted multiple times since then. I am on the latest IOS 9.2.1 software. I'm sure I am not the only person encountering this issue as it seems like an app bug.