I was able to unlock the T-shirt code in-game and got my verified email from bungie weeks ago. I was unable to log in and purchase until today for various reasons (Iowa Derecho storm). I logged in to try and purchase today and got the message that the codes expired on september 24th instead of the original 30th. There's another message that we can get another code from the 24th through Nov 13th but I don't know how to reacquire a new code. The triumph in game is already claimed so i can't re-claim that. How do I get a new code?
EDIT: go to your rewards page and scroll to the shirt and hit "acquire code" and a new one will be generated for you.