I forgot the email address I used to create my account.

You do need your email address. However, if you can contact a Microsoft Advocate they can help so long as you can provide specific account information.

If someone writes in to support and gets the first level (gamer support) then they cannot help at all. They do not have account access because they're just gamers like us. Only a Microsoft Advocate can help with that as they are official Xbox support

That clarifies things...however, the users I was referring to had spoken to support on the telephone...presumably telephone support would be above gamer support no? Unless there are various levels of telephone support of course?

If you know your personal information including the gamertag set up a call back with support as listed below. So long as you can provide some specific account info they can give you the email for the account.

In order to request a callback, please follow the steps below:

https://support.xbox.com/contact-us Click on "Contact Us" Select an option from the drop-down "What are you having trouble with?" Select an option from the drop-down "What's the issue?" Click "Next" Sign in if prompted. You will then be offered different ways of contacting Xbox Support, select "Request a call" and fill out the information that Xbox will prompt you for.

Nope, phone support is official as well. They should be able to help. Perhaps the people didn't give enough account info. When this happened to me years ago I had to provide old account info including recent purchases. Unfortunately at the time I didn't have enough info and had to go the Forgot route. Took me about 6 months to remember all the old info.

You do need your email address. However, if you can contact a Microsoft Advocate they can help so long as you can provide specific account information.

If someone writes in to support and gets the first level (gamer support) then they cannot help at all. They do not have account access because they're just gamers like us. Only a Microsoft Advocate can help with that as they are official Xbox support

Please do! I hope this works for you!