I can’t unlink my Xbox account from my call of duty activision account because it wants me...

There is no possible way for me to unlink my Microsoft account from the Activision support either as there is no way to change my email or recover my account through them. I am not paying for xbox live and call if duty again on my xbox. This means i am linked to an account that i have no access to as the email has been changed.

If you're not able to access or verify your identity with the Activision account that has the 2FA enabled and if the issue persist across any device or wifi network

You may need to reach them and see if it's possible to recover your account
https://support.activision.com/options

On the Activision account has the 2FA

Hi and thanks for reaching Microsoft Xbox gamer's community. My name is Josef.
I'm an Independent Advisor and a Microsoft Xbox user like you.

Hope you're doing great today despite this MOEZAKY3814

There is something that I don't quite get it.
The 2FA was activated in your Activision account or in your Microsoft account?

In any case, can you try using a different device, browser or wifi network to see if the issue persists in the sign in screen?

PS: The only way to unlink a third party account from your Microsoft account is log into that account and manually unlink it or work with their support (in your case Activision support)
From Microsoft side is not possible to unlink third party accounts

Solved it.

I went on the Call of Duty website, and unlinked my Facebook account, then deleted Call of Duty from my app list on Facebook, then relinked my account through the website, and now all is well.

~huzi