That is strange that your unlock requests have been continually denied. Have you had the phone for a period of at least six months? Perhaps sending a private message at the link below could help speed up the process, provided that you meet the requirements for unlocking the device.
https://forums.att.com/t5/notes/privatenotespage/tab/compose/note-to-user-id/192773
https://forums.att.com/t5/notes/privatenotespage/tab/compose/note-to-user-id/192773