So about the same time the note 3 came out, tmobile added the galaxy gear to their website under accessories, which makes sense because it is considered an accessory. They had at least two promo codes that could be used for accessories, "FALLFUN20" and "FALLFUN30" which would give 20/30% off all accessories. So a lot of people placed orders for the gear using these promo codes since it was first put on the site. As far as I know, they just started shipping the gear yesterday, so all of these orders were on backorder this whole time.
I placed two separate orders about a week ago for the gear using "FALLFUN20" for both to get 20% off. I waited this entire week with no updates on my orders. The order status page just said it was backordered, and the estimated delivery date was 10/10 (yesterday). I called them several times during that week period asking about the order, only for them to say they had no information.
They waited until the end of the day that the gear was supposed to be delivered (yesterday) to send me an email informing me they canceled one of my orders because the listing price was incorrect, and that I needed to return to the site and reorder it. When I returned to the site, the listing price was still the same ($299.99), the only thing that had changed is that they didn't allow the use of promo codes for the gear.
I immediately called tmobile and explained the situation, and they actually tried to spin it like they were looking out for the customer. "Because the listing price was believed to be incorrect, we are just asking that you replace your order to ensure you get a fair price, one that isn't too high or too low." So essentially they added the gear to their accessories, there were promo codes for discounts on all accessories, and people placed perfectly legitimate orders using these promo codes to get the gear. Then tmobile decided they didn't want to offer the discount on this one specific accessory, and tried to get away with voiding the prior orders and explaining it away with a complete lie. The listing price was always correct ($299.99), and the use of the promo codes was also correct. They canceled the orders simply because when customers were forced to reorder it they would now have to pay full price. This is complete bs, and t-mobile should be punished for even trying something like this.
After the first person tried to bs me, I asked for a supervisor and they said they needed to call me back. About an hour later they called me back and said they would give me 30% off instead of the original 20%. Interestingly enough, the first order i placed actually went through with the 20% off, and they only canceled the second order. So in the end I got one gear for 20% off and the second for 30% off which is the least they could do.
Please don't let tmobile get away with this. If your order was canceled the same way, call them up and don't let them bs you. They will eventually honor the original order.
EDIT: The only problem with getting the discount after they cancel your original order is that they force you to first order the gear at full price ($299.99) and then they add back the 30% to your t-mobile account, not to your credit card. In my case it was perfectly fine because I use t-mobile as my carrier and it will cover my next bill. If this won't work for you, hopefully you can get them to do it a different way.