Sometimes there may be a connection issue when unlocking an upgrade on iOS. If you think you have paid for an upgrade but the app content hasn’t unlocked please do the following:

Open the app and navigate to the upgrade page

Press the button on the upgrade page that says ‘Restore Purchases’

Tap this button and enter your apple account information when prompted

This will confirm with Apple that you have already paid for an upgrade and unlock the content without charging you again.