You may be entitled to a refund if an accidental/unwanted purchase is made.  But as the app stores are the merchants in this scenario, you can request a refund directly with them.

In order to obtain a refund, please send your request via the app store through which the purchase was made (e.g. Google Play) and in compliance with the refund policy of the relevant app store.

• To learn about the refund policy on Google Play:
https://support.google.com/googleplay/answer/2479637?hl=en-GB

• To learn about the refund policy on the AppStore: