Thanks for the request.
In general, if your device has the Google Play store, you should receive a follow up dialog to complete an in app purchase. Unfortunately, I only offer the pro version via this method.
If you do have Google Play on your device, please try to follow these steps (after each step try to purchase via the buy pro version button again):
- Reboot the device
- Open the app manager (e.g. "Apps", " Manage Apps", ...) in your device settings. Find the Google Play Store and press the "Clear data" button and "Uninstall updates". Afterwards, open the Play Store - you should be asked to accept the terms and conditions again and it will probably be updated again soon.
- Uninstall Deliveries completely. After reinstalling, the license will be checked upon first opening it again.
Sorry for the inconvenience!