That's what I have experienced in facebook pages. There's no way to dispute on Facebook warnings. You received that warning because of some people playing around and keep reporting your posts until that happened. Facebook automated system will warn you three times before they put your account under review if warnings related to "Nudity".
1st warning without block.
2nd warning, you will receive a temporary block for 24 hours.
3rd warning, you will receive a temporary block for 3 days.
4th warning, you will receive a temporary block for 7 days. Then Facebook will put your account under review. They will ask you for a photo ID. It will be hard to get your account opened again even if it's not a fake account. Be careful and use more than one account in your Facebook admin page if you received a 3 days block warning to keep your page.
*Don't count any warnings from the time you get blocked until your account is unblocked. Means if you receive 10 warnings in a short time "24 hours block" they wont count these warnings because your account was already blocked.
Goodluck