I have often seen people on Facebook announcing "I've been hacked", which is a very unwise thing to do, and also probably untrue.
If they had really been hacked, they would not have been able to access their account and post that message. But what I have noticed recently is that posting such a message immediately attracts swarms of hackers like bees to honey, and they swamp such posts with comments promising to rescue the poster's account from the clutches of the hackers, or to know someone who can do so. These messages are thoroughly disingenuous, because the account in question hasn't been hacked, but copied.
Spammers like to impersonate Facebook users by creating a page that looks just like theirs, and then invite their friends to become friends so they can spam them with ads for shady financial deals (usually involving cryptocurrencies), links to porn sites and the like. This is not hacking, it is impersonation, and is much more common than hacking.
If you suspect someone has been trying to impersonate you on Facebook, just search for your name. If you find a person with the same name as you, who has created a page that looks just like yours, using your photos etc., then report it to Facebook, and they will take the fake site down.
Similarly, if you get a friend request from someone you are already friends with on Facebook, ask your friend if they have opened a new account, and if they haven't, warn them that they haven't been hacked, but someone is trying to impersonate them. It's important to warn them that they haven't been hacked, so that they won't announce "I've been hacked" which is a sure way to invite real hackers to come buzzing around. If the new account does not belong to your friend, then you or they can report the bogus account to Facebook, and they will take it down.
But, whatever you do, don't say "I've been hacked" because if you do, you probably will be.
The hackers who come and offer to rescue your account, or recommend someone who can do so, will probably ask you for your login and password information so that they can "recover" your account, and that will make it easy for them to hack it, change your password, and hijack your account for their own purposes.
Remember, if you post a message saying "I've been hacked", then you probably haven't been, because if you had been hacked you wouldn't have been able to access your account to post the message that you had been hacked.