I am so sorry to read this, I had something of the same experience with my Trek 7.6. I do remember my first fitting at my current LBS when they told me if they just went by my inseam that I would take a 51cm frame, but I can't go > 48cm at most. I fully agree that the shop should take it back! Have you spoken with the owner about this? It is worth the conversation, and in the long run it would pay off for them...These things do get around!