The first thing you should do when your Facebook account is hacked is to secure it immediately [Call 1-866-825-1531 for Action]. Change your password, enable two-factor authentication, and log out of all devices. Next, report (this number 1-866-825-1531) the breach to Facebook. Check for unauthorized changes and notify your friends to prevent potential scams using your account.
https://www.devex.com/people/what-is-the-first-thing-you-do-when-you-get-hacked-on-facebook-2439040