How do I cancel deleting a child's Apple Account?

Nothing in there says there is a button to push to cancel the request and there is no email support. Use the link to contact Apple directly.

•  While your request is being processed, you can contact Apple Support with the unique alphanumeric access code you received, and we’ll help you cancel your request. After your account is deleted, Apple can’t cancel the request, reopen your account, or restore your data.

Another way to contact Apple Support if that one is not working for you is by either Phone or Chat by using this link here. For phone support, look up the number by region and for Chat Support use the section titled Get Online Support. After describing the issue you will be given the related Support Articles and on the bottom of the page will be a link for "More Options" and if Chat support is available in your region, you will be able to start the chat there.

Contact Apple Support - Apple Support

Review the Support Article here, especially the FAQ's that go over most scenarios including the deletion of a Child's Account. That account can be deleted by either initiating the request from the Child's device or the Organizer deleting their account, which will also delete the child's in that Family Plan. In that case, you would have received alphanumeric code that is only useful for a short amount of time to cancel the request while it is in the process of deletion and once done, there is no recovery.

How to delete your Apple Account - Apple Support

When i open your link, i could find only information with suggestions what to do to cancel request. There is also link to send the code. And when i go by that link it returns me again to the main page of FAQ

so i could not find the button to cancel deleting. Can you give me the support center email to right them about my request with code