Unfortunately, QR seems to be out of Disney Dollars right now. I've tried to cash out for them and although they appear in your cart and all seems well the next time you log in to QR your balance will be back up to precashout level. I guess when the pic is down the prize is not available...something I never knew.
I hope they are back soon since I don't have enough for a GC and we are leaving for Disney in a couple of weeks.