Hard to describe it, but it looks like attacker injected malicious js script but not on my side.
I was using fbc on Linux machine with different browser just for fbc.
My account has 2FA enabled.

I wiped all my browser history (all of it), tried on a different browser in private/incognito mode, I even changed the operating system (to Windows 10) and even DNS settings - everything was exactly the same - blank page with message about locked account.
In logs I saw loading a strange js sript so I blocked it with browser plugin and then then I managed to withdraw my funds.

I was acting in panic mode so I withdrawed all my funds by Instant method.
They are already on my wallet.

Messages form scammers:
https://www.talkimg.com/images/2024/04/09/Vqacg.png