If I had to guess, I'd think that OP put in a lot of entries into the September Sweepstakes for this item (found here:
https://1.shortstack.com/8DzfMr), but from what I can tell those sweepstakes are over.
If he has large quantities of codes my guess is that more than likely they figured out a way to hack the code progression like with the Google Home deal. Note that from the link you posted NY and FL residents are excluded and I think the OP mentioned only 1 per ADDRESS.