Yes - do pursue VS. I have been using them for 20 years and consider them a good airline to travel with. I am sure that you will find PE is worth it.
These kind of mistakes are happening to folks all around the world as we move from the time of booking through an experienced travel agent who caught all the loop holes for us - to the time of the web when we have to learn the loop holes. Fare Classes are a real nightmare for even the most experienced agent.