For iOS users: ( scroll to next question for Android ) Try to use the button from settings menu inside the game. Your premium should be back. If that doesn't work, log out of your Apple ID, then restart the iPhone/iPad, turn it back on and then sign back in with your apple id. Launch the game and try to use restore button again. Make also sure that in-app purchases are allowed on your device. If that doesn't work, please see this Apple article with further instructions.