Items bought through In-App Purchases (purchased with real money) are generally non-refundable. However, there are special cases where a refund can be granted, although the process for these transactions is handled by Google and/or Apple.

If you'd wish to request a refund for an accidental purchase, please check how to do it below:

Google - Android
https://support.google.com/googleplay/answer/2479637?hl=en

Apple - iOS
https://support.apple.com/en-ie/HT204084

Important:
You can easily manage the ability to make in-app purchases, adjust password protection settings, or disable in-app purchases entirely through your mobile device’s general settings. Further information can be found here for iOS and here for Android.