If the belt is genuinelty faulty then you can have a refund but without a reciept would be at the last selling price. The store may offer you an exchange but again only up to the last selling price, so if they are reduced now that is the price you would get. They wiil try to avoid this, but if it was a recent purchase and it is genuinly faulty there isn't anything they can do really, they have to refund u the last selling price in law. Do not threaten to take them to trading standards as you will waste your time, be calm and polite but firm. Also, just to add, most shops can track on their computer any purchase, and they only need to key in the batcode to check for a cash sakle of this item on the date your friend bought it.