If someone hacked your Facebook account and changed your email, phone number, 1-866-554-3839 and password, it's critical to act quickly to regain control. First, try to reset your password using the “Forgotten password?” option 1-866-554-3839 on the Facebook login page. Enter the email or phone number you still have access to, and follow the instructions to reset your password.
If the hacker has changed all recovery options, go to facebook.com/hacked and follow the steps to report the hack and secure your account. Facebook may ask for identification to verify your identity.
If you can't recover the account on your own, contact Facebook Support for further assistance. You can also call 1-866-554-3839 for support, though response times may vary.