I just spoke to a rep who also gave me this info. Whether this is true or not, I still call AT&T out on their BS. How did they not know they'd need a certain amount of SIM cards to match the total amount of inventory? They're AT&T, the seventh largest company in the United States. How did they not plan accordingly? At this point, it's just excuses after excuses after excuses.
I was told the same thing twice about the SIM cards being on back order with an Oct 5-16 delivery. That put me over the edge to cancel my order and buy one that was readily available at noon today at my AT&T store .