I know a lot of stores will (Petsmart and PetCo, most small pet food stores, etc.) but I don't know how an online store could do it--return shipping would be prohibitive and anyone could SAY their dog didn't like the food. Unless it's defective or arrived damaged they probably aren't going to refund it.
You could donate it to a shelter or to a friend who has a dog with a tougher tummy.