Where is the banned users section?

Could someone please explain why the administrator downgraded my status to observer and subsequently revoked my access to that specific PDF? I find myself completely unable to view the document titled MESSAGE, WISHES, COMMENTS.
I am quite interested in understanding the underlying REASON for this restriction.

Thank you.

The Observer isn't an admin, so he didn't just go around stripping access to Amtrak out of nowhere.

The whole reason that access was pulled is because of all the spamming and the general disregard for the rules governing that subforum.