I didn't take the time to read all the responses, however I wanted to say this. If this had happened to me, I would look up on the internet the name of the owner of the shop. I would send a personalized letter to them explaining what had happened to me on my visit. One thing I try to do is start such a letter with a compliment i.e., "I wanted to let you know that you have a lovely shop, however, I would like to let you know about my visit. It would be a shame if a lovely shop such as yours were to have to close due to poor customer treatment by your staff." I once had a boss that told me, "You can't make someone care when the DON'T". I am so sorry for your experience.