I tried to check out and the item in my shopping cart disappeared, what happened?

I tried to check out and the item in my shopping cart disappeared, what happened?

We are sorry that you were not able to complete your order. Our stock levels are live and your shopping cart reflects what is in stock at that moment. Placing an item in your shopping cart does not guarantee your right to purchase that item. Until you have completed the checkout process, another customer may purchase the item even if it is in your cart. If that happens, you will receive a message on the shopping cart page informing you that the item is no longer available and that you should remove it from your cart.