Reposting since I think this is still relevant.
My order is still active, using the same card that I had previously used on Walmart.I've ordered from Walmart.com a couple months ago, and I might be able to explain the credit card cancellation issue.
Walmart's systems are overly strict; if you have a new account and the website doesn't like your credit card and/or your purchase, the website will cancel your order. You have to call Walmart customer support to get the website to accept your credit card, and then you can place the order.
The CS rep I had was great so it didn't take long, but it's obviously long enough for you to miss the pre-order.
I got lucky with my pre-order, visited GAF 20 minutes after the thread went up.