Time to write to your credit card company why you are not paying that part of the bill. Then they'll do a charge back and you'll be happy. You did use a credit card to pay for this, right?
Not me. I discovered in college what a mediocre play I was. During the 5 hour trip up to Mammoth for skiing, I would play with a friend who was an Expert (one rank below Master, I believe). To make things "fair", he wasn't allowed to look at the board. I never won a game.