Rogue One is right. The retailer is under no obligation to sell you a product at ANY price.
Just because someone made a mistake, doesn't mean you get to gain from it. That's actually pretty messed up.
In fact, I have had a couple customers order something, and based on their email correspondence with me, I refund their money and tell them I don't have the product... I just don't want to deal with their inevitable BS.
If someone in front of you in line drops a $20 bill, do you think, "WOO, FREE BEER!" Not cool.