Hi! To request a refund for in-game purchases, you need to sign in with the Microsoft/Xbox account where the charges were made, then go to the Xbox refund request page, find the purchase, and select the option to request a refund.
https://support.xbox.com/en-US/help/subscriptions-billing/buy-games-apps/refund-orders
Please note that refund approval is not guaranteed, since it depends on Microsoft/Xbox refund eligibility. If you do not see the purchase listed, make sure you are using the correct account.