Fortunately, HA eventually got back in a support email with the code
Originally Posted by
philemer
It would be SO easy for HA to put these discount codes into your online acct. Just like AS does. Sad that they don't.
It used to be right in the account and you could see it after signing in. Ever since they changed the website it hasn't worked and the email with the code even says something to that effect (but without saying if or when they will fix the problem)