Please check that you are logged in to the GooglePlay Store with the same account that you used to purchase the app. Check here which email was used to purchase the app: https://solutions.mycarly.com/users/request_accounts_info
The full version of the app can only be restored using the same GooglePlay Store account.
If you are logged in with the correct account, it is sometimes necessary to restart the phone.
Then please clear the cache of the Google Play Store in the Android settings.
In some cases it is necessary to log in to Google Wallet (see Internet) and download the app from there again.
Unfortunately, this problem occurs occasionally with the Google license administrations.