Backordered Ipad Mini 4 128 GB

On Saturday I went into one of my ATT stores to inquire about purchasing a new Ipad to replace one that was stolen when my house was broken into. I say the display for the 128 GB Ipad mini 4, and was all set to set up the plan to purchase it. They didnt have any in stock and were willing to place an order for me to have one shipped, which was fine by me. I wanted the extra memory, and the 64 GB was the same exact price on the monthly plan (which was weird, so why not have double the memory for the same price?). 

Here I am expecting a new Ipad this week, and only after chatting with a representative online did I find out it was backordered. This is after I already paid the tax on the item, and was assured I would get it this week. It would be in the best interests of the company if all available information about inventory was available so that as a customer, I can make the right decision about my purchases. I have been a loyal customer for over 10 years, and while I have had other issues at other times, I wonder if the amount that I pay is worth not getting the products I should receive.