Bought a brand new MacBook last year and set up a fresh iCloud account to go with it. Problem was for the First and Last Name I entered some variant of Unknown User / Unknown Account (for privacy..) and chose a username “user.mailbox.unknown@icloud.com”. Everything was fine but 24 hours later, I could no longer sign into the account. It was saying my password was incorrect! I was 100% sure this password was right so wtf? In a panic, try to remove the account from my brand new device and can’t! You have to sign in normally to remove an account in settings. Obviously I called Apple support and a high quality American sounding woman took my call. She said my account appeared like it had been deleted, like when a user deletes their own account. She placed me on hold and found out what’s going on. Apparently “engineering” had my account DELETED. My only guess is they didn’t like my user name / mailbox name and suspected I was a fake person. Anyways the lady was able to get my account temporarily reinstated right there on the spot and I was able to login and delete that toxic account off my Mac. I made a new account and everything’s working fine. Needless to say I was very impressed with how they handled my situation, within 20 mins no less.