You think your account was hacked or someone is using it without your permission

Try Guided Help
Facebook guided help tool can walk you through the steps to resolve your issue.

Get Started
If you think your account has been hacked or taken over, you should visit this page to secure your account. Facebook will ask you to change your password and review recent login activity.

Your account may have been hacked if you notice:

  • Your email or password have changed
  • Your name or birthday have changed
  • Friend requests have been sent to people you don’t know
  • Messages have been sent that you didn’t write
  • Posts have been made that you didn’t create

You can also review these tools and tips to help keep your account safe. You may also want to learn how to protect yourself against malicious software that can potentially compromise your account.
Note: If the email associated with your Facebook account has changed, you can reverse this. When an email is changed, Facebook sends a message to the previous email account with a special link. You can click this link to reverse the email change and secure your account.

Source: https://www.facebook.com/help/203305893040179?helpref=uf_permalink