Account safety

reportarla como robada en xbox para que bloque tu usuario

Check this steps by step support guide if you think your account was compromised: https://support.xbox.com/en-US/my-account/security/compromised-account-solution

Hi there Xton

Sorry that you have had this situation, I always suggest not to share your details at all even with friends (that is also against code of conduct if it is "sold" to another user please report it to get it shut down) Also change your password every month
is the best way to keep stuff secure to be safe.

Definitely change the password to any all Microsoft accounts you have access to that may have been on that console. Through the Microsoft account website, Xbox.com, or another person's (one you trust) console you can try and set up two-step verifications
(texts you a code/emails you one you have to put in manually) and a login passkey that should, in theory, transfer over to what ever account is trying to be logged in no matter where its logged in from.

There isn't a way to remotely remove an account from an Xbox One, but as mentioned if you change the password on the account, that will lock it out and the other person will no longer be able to use it.

Also consider adding two factor authentication if you haven't done that already.