Inventory available for pro purchase is constantly fluctuating due to retail demand. We do try very hard to keep inventory updated. Because our manufacturers drop ship and fill pro orders after retail orders, some of these are occasionally canceled before being updated on the site.
You should receive a cancelation email notification when an item has been canceled, where you can view the cancelation reason. You will not be charged for the item or shipping the item.
If you have yet to receive an email confirmation for your order, or you don't see it in your order history, it's possible your order did not complete correctly. Please reach out to customer service to verify your order.