I have forgotten my Microsoft Email, but remember my Xbox 360 Gamer tag. What can I do?

You can't log in without the email address and, far as I know, you can't recover the account without it as the email address is the main way the system identifies your account

Not sure if this page would be useful or not

https://support.xbox.com/en-GB/help/account-profile/manage-account/forgot-microsoft-account-solution

Could try this as a last resort but there's no guarantees as not sure whether it asks more info or not:

Account Recovery

Hello, first it's a pleasure to be able to help you today.

My name is welcome to the community.

Hello MattHeinrich2, unfortunately it is not possible to log into the Microsoft account without knowing the email or if you have placed a phone as a login, try to see with a family member, friends you play if they do not know your email that used on Xbox, then to cancel the automatic renewal of the subscription enter your account by the link below.

https://account.microsoft.com/services

How can I get my old gamer tag....I can't remember the email

That's incorrect. It's like this:

A is my main email with the gamer tag I want GONE.

B is my old email with the gamer tag I WANT.

C is a Microsoft account I made to move gamer tag A to.

I just want to understand if I'm doing anything wrong here.

I downloaded both Xbox Live profiles to a 360 quite some time ago and made Microsoft account C around the same time. I'm afraid to use the Xbox One I bought a few weeks ago because I don't want to reset any timers. I'm looking to close old email accounts
I have, and the one my main gamer tag (B) is attached to is one of them, so I need to move it to my main email (A).

I do not have the time to make phone calls, and the chat system will not work for me due to the issue that's shown in the imgur link.

passport.microsoft.com is not working it says not even a web sight. so this is what i do i go to my account and click Privacy and Online Settings, then it says Parental Approval Required so i log in has my alt email/the parental email. one problem is my
parent email might have 2 Xbox accounts set on it because when i log in it does not have the same gamer tag as my Xbox parent Xbox account but i get emails form Microsoft addressed to my parent gamer tag (i have not change the gamer tag since i am the parent
account so it is still the random words but i know what it is when i see it) and thank you for try to help and hope fully we can get this fixed