1.
Refunds are not guaranteed. For more information, see the Terms & Conditions.
If Apple has notified you that it is not eligible then so be it.
We can't help you, sorry, we are also users of Apple products & services like you.
2.
To avoid the case in the future, see:
Require a password for App Store and iTunes purchases
Require a password for App Store and iTunes purchases - Apple Support
Manage App Store purchases, subscriptions, settings, and restrictions on iPhone
Manage App Store purchases, subscriptions, settings, and restrictions on iPhone – Apple Support (UK)
Prevent in-app purchases from the App Store
Prevent in-app purchases from the App Store – Apple Support (UK)
if you still need help, get more help and assistant from Apple directly, see Contact Apple for support and service -> Contact Apple for support and service – Apple Support (UK)