Ensure you're using the most recent version of Bonza National Geographic by downloading any updates from the App Store.
You might have restrictions on your device preventing you from making in-app-purchases. Go to your device settings, tap “General” and then navigate to “Restrictions” if restrictions are "ON" this may be preventing you from making In-app Purchases.
If you’re still having issues, send an email to firstname.lastname@example.org and include which purchase/s you are having issues with and which version of iOS you have. We will get back to you as soon as we can.