Welcome to the community!
Are you the owner of the account? If you are, it's possible that you selected subscriber rather than account holder when you registered for My Account. You would need to contact customer service to change your account status. In addition, they can also be contacted via Live Chat, Facebook, or Twitter. Those methods can be accessed via the contact page posted above.
The details of subscriber vs account holder My Account access can be viewed here.
Hope this helps 😀