A list containing those folders that you have subscribed to is located in your "Mailhub account". Sometimes, the entries can become out-of-sync with your real list of folders. This is often seen when different e-mail clients are used to read e-mail.
By clicking on the "Folders" button, you can perform operations on the list of folders. In order to see the entire list of folders, click on the "Show Unsubscribed" link. In order to clean up your subscribe list,