Wow, I cannot imagine paying $500 for such an event. Before giving your credit card info, you should have made sure you knew the seat assignment. This is a bitter lesson that should stay with you.
You said, "Let me say that I am high in the corporate world and I have never been treated so ignorantly." Sad to say, but you were the ignorant one. You did not do your research. Also, your bragging about your position sounds self important and certainly will not help your cause. I really do not think you will ever see a refund.
I agree with other posters. Contact your credit card company and dispute the charge. I think will be your only recourse.