“Glass sucks. The back of my phone shattered when I dropped it and it dawned on me that glass is faulty. I never had this problem with aluminum. I have determined that glass as a whole on iPhone is faulty since my phone is broken.”
See how silly this sounds, OP?
Usually they discount the watch by the value of the gift card, then charge for the gift card separately.
So jf you add up both amounts it should come to the total you were expecting.