Missing Gamertag

Your gamertag was found violating xbox lives code of conduct therefore it was changed. From reading the gamertag it may be seen as impersonating staff since they have usually Miss, Mister, Misses, (etc) in their gamertag and they are official staff accounts.

If you think your account may have been compromised then you would need to call 1 800 4 my xbox and let them do an unauthorized access.

The thing is with xbox support before they can even get into the account to show them any information about the account they have to verify ownership of the account. by sending out a verification code to any billing, or security proof email or phone number
that may be on the account. it just has them hit a button and it sends it out to whatever is on the account.

if you think your account may have been compromised and someone changed the email on the account xbox support can do an unauthorized access escalation but you would need a xbox console that the profile in question was on previously because part of the escalation
will ask questions about that console.

two things

1st only phone or.chat support can help you with this

2nd and this is important

If you didn't login within 5 years they reset the gamertag and issue you a new one but it doesn't affect your dlc

Thst.being said

You must.not.be using the right ms account

You are going to have to.keep.trying

Support cannot give you the right email unless you have the right pii for the gamertag

If it's corrupted delete it (just the GT!) then use the recover gamertag feature to retrieve it again.

Once your account has an active live membership going you should be able to re-download the contact and talk to everyone again. Please let me know if things aren't sorted out after you get your membership going again!