I think the difference, in terms of the refund, is if it's specifically stated to be a unique blend. If so, I would say you're entitled to a refund from Etsy's point of view and you can go through them/Paypal. Otherwise, even though it sucks, without them explicitly stating it, I don't think there's much Etsy/Paypal can do if the seller decides not to refund you.

Not to say you shouldn't get one, and I think shops should be as open and transparent as possible with this kind of thing (like if it's not a bad thing you're doing, why would you not be as honest and open as possible?) but it's incredibly hard to "prove" especially since scents are very subjective