FB(LiveChat)What if someone hacked my Facebook and changed my email, phone number, and password?

The first thing you should do when you suspect your Facebook account has been hacked is to change your password and contact Facebook help center +?-[???]-???-???? or +1-$-???-$-???-$-???? (Contact~USA). This step is crucial to regain control of your account, especially +?-[???]-???-???? if the hacker hasn't already locked you out.