If a purchase is accidentally made on your Android device by a friend or family member using your account, it is possible to request a refund. For more detailed information, please, refer to: 

https://support.google.com/googleplay/workflow/9813244

If you discover a Google Play purchase made with your card or other payment method which you didn't authorize and wasn't made by anyone you know, please, report unauthorized charges within 120 days of the transaction at: 

https://support.google.com/googleplay/answer/2851610?sjid=7478795453529829610-EU