How to recover?. I don't remember my email user but remember the password and GameTag :(...

Hi my friend, how are you today? So about your problem, I suggest you seek and call to MS Support first, you can access in your idiom, only you need is follow to this link https://support.xbox.com/us-en/contact-us (where
have /us-en/ just change for your idiom like /pt-br/ or /fr-fr/ ) so then just wait and talk with some human agent

Hey there! There’s a special form here for when you’ve forgotten or lost certain account details and are trying to recover access. Best of luck to you getting back your Gamertag, cheers!

http://account.live.com/acsr

You can also try this recovery troubleshooter if you don't remember the email address:

https://support.xbox.com/en-US/my-account/microsoft-account/forgot-microsoft-account-solution

Make sure to follow the steps exactly and provide all information.

You can recover your gamertag if you remember the email and password with it.

Hi and thanks for reaching out. I hope you’re doing well. I'm an Independent Advisor and a Microsoft user like you and I'll be happy to help you.

You can follow the steps here; https://support.xbox.com/help/account-profile/m.... If it doesn't help you, then I'm afraid there is no other way to recover your account.