like Products you get from any other store you don't need to pay for a product that did not work. For example you buy an iphone X at walmart and it was a fake iphone. You just need to give it back and if you made a payment on it you would need a refund. Other than that give the item back and refuse to pay for it if the product did not work. You can not keep the product but you can give it back and not allow the collection of payment from the person who gave you the treadmill.