Walmart false advertising and deceptive sales tactics St. Louis Missouri

I was recently alerted to a deal on Walmart's web site for an upcoming video game called Unreal 2. The web site had stated that the price was $17.97 and that the game would ship in January. I purchased this game with a Visa and received an email confirmation of my purchase that same day.

Many of my friends also purchased this same game due to the very low price. The next day, Walmart had the game listed for $49.97. I suppose the original price of $17.97 was a mistake. Regardless, my order had been placed and the confirmation was received. A week later, I received another email from Walmart. This time it was from the video games department.

The email stated that there was a problem with my order and it had been cancelled. They used this same line of B.S. in an email to every one of my friends who ordered the game as well, just so they wouldn't have to honor the original price on the web site. This seem illegal to me. Is there anything I can do? I have a printed copy of the email confirmation. Can I take this to Walmart when the game is released and demand they give it to me for that price?

Thanks in advance,
Steve
St. Louis, Missouri
U.S.A.