Gopros weigh enough to be put on scales, you're probably pushing your luck. But hey, if you can't refund it just sell it and try again at another store
DNA will hit much better. If you have that many orders and account history you should hit for something big. Refunds for account history like that are given basically no questions asked for order <=$500. Something higher than this you can still refund with DNA but it will just take a bit of SEing. Still very easy.
May be better to try and hit something more profitable, with such a good account they'll believe whatever you tell them. Maybe some graphic cards that you can sell fast