Your Premium is tied to your account, not to your phone. To get it back:
- Open the app and sign in with the same account you bought with (same email, or the same Google or Apple button).
- If you bought on the App Store or Google Play and still don't see it, tap "Restaurar Compra" (Restore purchase) on the Premium screen. Your phone must use the same Apple or Google account you paid with.
If it still doesn't appear, follow the steps in Premium not recognized.