Retrieving locked Apple Account with 28-character recovery passcode for iPhone X

I have forgotten my 24-character recovery key for my Apple ID and therefore cannot disable the Activation Lock on my iPhone X (IMEI: 3********0, Serial No: F******LF). I have already tried logging in with my Apple ID and password, as well as attempting recovery through iforgot.apple.com, but I was asked for the recovery key which I do not have. I also checked my trusted devices and email, but I do not have access. I am requesting Apple’s assistance to verify my ownership using my purchase invoice and device details and help me regain access to my device.

[Edited by Moderator]

Original Title: How do I retrieve locked Apple Account with 28 character recovery passcode? I had my iPhone stolen and the thief, being generous changed my passcode