Hi Adriana PE
I’d like to clarify that:
If a Microsoft account hasn’t been used for an extended period, it may already have been closed under Microsoft’s account activity policy. In most cases, you need to sign in at least once every two years to keep an account active. After that, an inactive account can be closed, and if it’s been more than two years, it may have been permanently deleted and can’t be reopened. In that situation, there isn’t anything left to deactivate or delete.
You can review the details here: Microsoft account activity policy – Microsoft Support.
If you’d like to check the status of the old address: Try signing in at Outlook.com with the old email. If you see a message like “This account doesn’t exist,” it likely means the account has already been deleted.
I hope this helps clarify things for you. Thank you for your time. Have a lovely day!