http://google.com/search?q=gamestop+return+policy
Yes, Gamestop doesn't have a refund policy per se. That said, its policy is geared to the items it sells, which are mostly software. Hardware is an exception. If you have a defective product and you return it within a few days, you have the right to an IMMEDIATE exchange. If they don't have stock on hand. You have the right to demand a refund.
There are two ways to do this. You can go back on their busiest returns day of the year (either tomorrow the 26th or the 2nd), and make a scene. Refuse to budge until you are satisfied.
If you aren't the confrontational type, which is totally understandable, then whip out your phone and get the whole interaction on video. Get the manager's name and his statement recorded. Make sure it's date stamped. Post it on Vimeo or Youtube. This will be your indelible proof of "a reasonable attempt to return a defective product," if it goes to arbitration. Next, contact your credit card company and dispute the charge. Then, go buy at some place else.
I do not recommend palming your problem child off on some other unwitting buyer. You already have your Xmas messed up. You don't want to ruin Xmas for somebody else. Bad karma and all that.