What to do if someone hacked my Facebook page?
If you are unable to access your page, first check whether another Facebook page administrator or someone with full control over the page has deleted you. Contact the administrator of the Facebook page or the person with full control over it and ask them to restore your access.
If your account is hacked, report it here https://uk-ua.facebook.com/hacked.
Try step-by-step help here - https://uk-ua.facebook.com/help/203305893040179/?helpref=related_articles.