How do I unlock my iPhone 12 after logging into someone else's account?

Hello! I logged into someone else's account on my iPhone 12, and now my iPhone is locked. The iPhone is now logged into Telegram. They demanded money to return my account. The iPhone remains in iCloud as a trusted device, but there's no unlock button. What should I do?

[Re-Titled by Moderator]

Original Title: Apple DaniliPhone 12F17********