Refund - My Child Purchased Something by Accident
Apple
It is possible to restrict purchases in apps please refer to your device Settings for Parental Controls.
Google
We have done some searching around and found a nice tutorial on adding a pin number to the Google Play app so this does not happen in the future.
http://support.google.com/googleplay/bin/answer.py?hl=en&answer=1626831
As developers we feel that this should be included and enabled as standard to both avoid accidental purchases and unauthorised purchases. We would rather lose the sale initially than have unhappy customers.
Please refer to our Knowledge base article on our refund policy - https://fullfat.uservoice.com/knowledgebase/articles/120034-refund-policy