I think there's a good chance you can get Amazon CS to refund the money you paid for the Amazon GCs (not return but refund ie $20 free for each GC) considering that you only bought the GC as part of a bundle and you wouldn't have bought it if not for the sale. But be prepared to spend at least 15-30 mins explaining the sitch either on the phone or via chat - Amazon reps are not the smartest bunch.