If you get an error message that says "Unavailable for purchase, this item is for use with an application purchased with another Apple ID. If you receive the error message "This item is for use with an application purchased with another Apple ID.", it is likely that the Apple ID you used to download smash. and the Apple ID you are trying to register for Premium are different. Please take one of the following actions before trying to sign up for Premium.
Sign out of the iTunes Store / App Store and sign in with the Apple ID you used when you downloaded smash.
Reinstall smash. with your current Apple ID
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