M's usually lets you return something even without a receipt. The manager at the M's here told me that they can tell if it's their item; that it will show in the computer when they run the SKU. The down side is that you just get store credit for whatever the lowest price is of the item. But at least that way, you'd get some money back. The other option is to contact MM directly. The number on their website is 1-800-286-5263. I hear that their customer service is awesome!