kid's unauthorized purchases refund policy

In the last 4-5 days i found out my 7 year old discovered my apple id password and made lots of purchases from a game app WAR ROBOTS amounting to thousands of dollars. Yesterday was his birthday:) I don't want to grill him, i don't think he really understood how much he has spent.

went back to my purchase history and tried to report the problem for refund. It keeps saying not eligible for refund. No explanation as to why. I read the refund policy still don't know exactly what apple's approach is to these kinds of situation.

How should I contact who? I have been through apple support map, trying to pinpoint the right email/phone etc.

I need help