If in fact the product was indeed defective, the store 'should' have taken it back and sent it back to the manufacturer as mentioned before without a restocking fee. The store should have also tested it in the customers presence and made a decision then, if the product was in acceptable working condition then the restocking fee could apply. . At least thats what I would have done... The store also needs to post a reminder in clear view of patrons so theres no dispute.