Sign in message states that the account does not exist after disassociating it with gamertag

My home business email was associated to my gamertag and I disassociated it as a primary alias to my xbox live gamertag for professional reasons and when I went to log in to my email it said that it does not exist.  I tried emailing my email from a different account and it came back as undeliverable.  I then tried to recreate the email with the same email address and it said that is was already taken.  Please help me with this issue.  I help adults with developmental disabilities and it is important that I am able to maintain that account.  Please help me resolve this issue.