I understand that this whole situation is ridiculous and frustating, but I reccomend that all those who ordered the figure, and if it's important for them to have the figure, to resume your order with the adjusted price. I say this because if you cancel your order there is no guarantee that they will be available if you finally decide to order them later.
Believe me I'm on your side (having gone to C-IV), HTS made a deal and they should stick with it. Obviously somebody over there screwed up and failed to disqualify the C-IV exclusive from their promo, and that person is in the doghouse. But, really, the company should honor their deal, just as SWS.com, dropped the price on the Lucas Family set after it many preorders were taken.
Hopefully HTS will come to their senses and honor your original deal, and credit your account accordingly,but if you really want the figure I wouldn't hold my breath. Lets face it HTS is not the most organized e-tailer. My account still lists an order as "unshipped" that I recieved months ago. My Kir Kanos comic packs came bent. My buddy ordered 10 DSTs, then was informed he could only order 2 at a time. He ended up completing 5 orders of 2, then the next day they cancelled ALL his orders. He called them and they said he couldn't order so many of the same figure, but they couldn't explain why all the orders were cancelled. Of course now they were out of stock.
Ideally the McLukes will be in stock long enough for the next big HTS promo, but there's no guarantee that they will (then again 501st SS anybody?). I know I've waited too long to order exclusives and had to pay heavily down the road to get what I wanted(at C-IV BTW).