Looks like they have some problems processing the orders for premium. My order details state that "This order may take up to 4 hours to process but usually will take less than an hour". Hopefully they'll have it sorted out soon.
I also called this AM and they also mentioned the technical problems above. They did say that it should be fulfilled by the release date. Ultimately, it's probably no big deal as you would need to be able to launch the game to enter the key for premium if I understand correctly, and you will not be able to do that until it is released.