While I don't think the charges were necessarily out of line, and I don't think you have a real beef... at the same time, I don't think they are wise on the part of the shop.
I don't think that shop has a clear grasp of the concept of "marketing" the "experience".
In other words, fair or not, you still don't much feel like going back to the shop. How not to compete with bike-stuff-at-low-prices.com.