I want the email for this username

Hello!

Hope you are well. I'll be glad to assist you.

I am very sorry that you are going through this situation. Please note that Microsoft support cannot tell you your email address, even if you know your gamertag. They only offer some steps to identify the email if the account is open on other devices, you can check it here

https://support.xbox.com/help/account-profile/m...

When this happens, users must identify if they sent an email to someone from their account, so they can check with that person for the email address from which they received the message.

Additionally, if you have an active subscription you can log in to this site from any other account.

https://account.microsoft.com/billing/payments

In the “Transactions” section select “Investigate” and enter the data requested regarding the payment of your subscription, this way the system will give you a clue of the account from which the payment came from.

I hope the information has been clear, I will be attentive to any questions you may have.

Best Regards.

Or you could change it slightly. For example: I Fallensource I, or x Fallensource x. You would still have the name you desired.

sorry you cannot request a name that is being used, FYI Live is not the only service that uses the game tag system, windows PC games and Zune do too. you will just have to pick another name.

Smwutches is correct it is being used
live.xbox.com/.../Profile

Just to add, the system doesn't see things like spaces as making a gamertag unique. So Fallensource would be the same as Fallen Source (which is being used).