The first email is contradictory, stating they can't refund your order then saying they can. A moot point, as you're covered by the distance selling regulations anyway, giving you the right to change your mind within 7 days from the day after the goods arrive. If the goods are faulty (and a topbox designed to hold things and keep them dry, with a hole in the bottom, must surely be faulty!) the seller has to pay return postage costs too.