Refund Decision - Child Purchase

My child made a large unauthorized purchase with Roblox due to the Apple Ask to Buy function not working. My refund request was denied and my appeal to the decision denied. Any advice on how to escalate this issue? I’ve spoken to support twice and they haven’t been able to assist me or provide a reason why they denied it despite it clearly being a minor making an unapproved purchase (13 transactions in a short period of time with a large amount spent) Thank you!