I bought a cake, and when I ate it, it tasted spoiled. I bring it back to the store and tell the manager that I want a refund because the cake tatsted spoiled. The manager refuses the refund saying the cake was made that morning and everything is fresh. He calls a customer and asks for an "unbiased" opinion. The customer tastes the cake and agrees that there is nothing wrong with it.
According to halacha, is the seller responsible for issuing a refund? There is no statement that guarantees the cake's freshness; nothing saying that you can return any dissatisfied item for any reason (no stated return policy). Since everyone's taste is different, I may not like the taste and judge it as spoiled while someone else may not.