While we understand your situation, we are generally forbidden by privacy laws against giving unauthorized access to someone who is not an account holder. It is for this same reason we cannot remove the account by request.
We also cannot remove an account without clear proof of violation of our terms. A common violation would be the account falsely claiming to be over 18 and publicly showing that they are under 18.
If you wish to have your child's account removed you will need to gain access to the account to cancel it or have your child cancel the account.
We encourage you to use software tools on your own computers to assist in overseeing your child's Internet access.
If you have any additional questions, please contact firstname.lastname@example.org.