Amazon fail

Amazon's customer service is horrible. I pay for Amazon prime. This costs $80 a year, and you are supposed to get free two day shipping on in stock items. On Thursday the 4th, I ordered two books that I need for work, and the items were listed as being in stock. I expected them by Monday the 8th. They haven't even shipped yet, and the expected delivery date is now showing up as next Friday the 12th. I tried to cancel the order, and a reply by automated message said that I could not, because the items had already shipped.

So, I contacted customer service, and they said:

We normally obtain the books from a supplier who can usually send it to us as soon as possible from the time your order is placed; however; in this case, the supplier has taken longer than expected to make this item available.

Our reliance on suppliers and manufacturers for information about their stock means that, occasionally, our database will not reflect all changes.

I've checked and it looks like we’re waiting to receive more inventories for your book. Though we're unable to give exact date when we can obtain stock or ship your order at this time but rest assured that we're working with our suppliers so that we can try to have your order shipped as soon as possible. I hope you'll understand that we do our best to ensure that all of our customer orders leave our fulfillment centers as fast as we can.

 In other words, the item is not in stock and never was. They are merely a middle man, and don't have anything in stock. In the meantime, I can't cancel, so I am stuck waiting. Maybe Amazon is slipping, and I will have to go back to buying from brick and mortar stores.