It usually just means they have (pre)sold out of the stock that they ordered for this particular release. Or, in some cases the manufacturer has requested orders only be made available for a limited window of time, usually when a company is nervous about being hit with a cease and desist from the license holders. Either way, if you log into your account you should still see your order there.
This is a pretty normal thing with third party releases on any number of sites, removing the item/product page as soon as they have sold through their stock allocation, or otherwise marking it as no longer available (or something similar) if it's a site that does leave the product page up. Nothing to worry about. If you got your order in you'll be fine.
I just wish I knew what the full price will be, because it only lists the price of the deposit ($15)
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