Please note that there are 2 separate HappyCow apps (“HappyCow Full” and “HappyCow Free”). Please ensure you have the right one installed.
If you updated previously from the free version using the “In-app Upgrade”, to test, open the free version and visit the “Trips” page from the menu in upper left.
On this page are you seeing “Create a Trip” or an ad to Upgrade?
If it says create a trip you have the full version already. The text on the splash screen which you see when the app launches, have the word “Free”, but that should be removed on the next launch of the app, once you fully close it or restart your device. However, the app name on the icon will remain called “HappyCow Free” even though it’s been upgraded to the full version.
If instead you’re seeing the ad to upgrade, if you’re certain you’ve logged into the Play Store with the same user ID which you used previously to buy the upgrade, then you should not be charged again. Click on the upgrade dialog and the process should successfully complete without charging you.