Hacked child account

I’m hoping someone here can help or point me in the right direction.

My son’s Microsoft account has been compromised/hijacked. It is a child account that is part of our Microsoft Family Safety group, which I manage as the parent/organizer.

We no longer have access to the account. The password and/or security information appear to have been changed without authorization. When we try to recover the account, Microsoft reports that the account does not exist, yet we also cannot create a new account with the same email address because it is still in use.

The account is still visible in our Microsoft Family group, but sign-in is not possible, and with another mail account appearing.

The main concern is that this account contains purchased digital games and content, and we are afraid of losing access to those purchases permanently.

I can verify ownership of the account and purchases as the parent and Family Safety organizer, including payment details, purchase confirmations, and account history if required.

Has anyone experienced something similar with a hacked child account under Family Safety?

What is the correct escalation path in this situation?

Is there a way to recover or secure the account when standard recovery fails?

If the account cannot be recovered, is there any official way to restore access to the purchased content?

Any guidance on how to proceed or how to reach the right Microsoft team would be greatly appreciated.

Thank you in advance.