I would think it would be obvious to speak to the Store manager, or find an online source to go higher up the chain.
That's exactly what I was referring to. Boycott? Fine, but there's no need to go off on the lowest level workers. It just makes the person who is ranting look like the ass he is. Go off on the manager, fine. Tell off the customer service or marketing people, knock yourself out. Maybe it will make a difference collectively.
But going off on a retail employee in a local store is pretty much the definition of being a coward. Lashing out at someone who cannot even argue with you without risk of being fired. How brave!