FB lockout

Scam, scam, scam (highly likely).

Only log into FB from the facebook page itself.

Also, FB is more likely to ask you to identify pics or upload images of your IDs.

Go to another computer - anywhere. If you've got kids, neighbors, the public library; it doesn't matter. Try logging in from there. If you can, then your problem is on your hard drive(s) and I would guess it's malware. If it is, then either remove it yourself or lean on a skilled friend or contact a company like Geek Squad.

If you can't log in, it's possible that the password changes you think you've been making haven't gone to FB at all; they've gone to whichever spammers/identity thieves sent you the first notifications. So if you cannot get in but it claims a password problem, have FB (on this other person's computer and NOT your own!) send you a link to change your password. However, it would probably still pay to run anti-malware programs before changing your passwords.

Anti-malware programs:
* Norton (decent but expensive)
* McAfee (probably came with your computer; seems to be okay but not all-inclusive)
* MalwareBytes (decent and free)

But if you don't know what you're doing, please either lean on someone who does (and buy them lunch to thank them for their efforts) or head to Geek Squad.

PS FB could have, possibly, sent you such an initial notification. But it feels suspect. I am not, though, dismissing it as 100% unlikely. But this whole thing looks to me like you got phished.