Purchases are made through Google Play or the App Store, so refunds are handled by them.
- Google Play: open play.google.com, Order history, find the purchase, and choose Request a refund.
- Apple: open reportaproblem.apple.com and choose the purchase.
Stopping purchases
Turn on purchase approval in Google Play (Settings, Authentication) or Screen Time on iPhone (Content & Privacy Restrictions, iTunes & App Store Purchases).