If he's been trying over the past few days, a lot of those guys have been gone all week for Interbike. Fron their website, posted on Sept 14th:

"The Leader Bike office will be closed from Tue (9/21) and re-opening Monday (9/27) for Interbike in Las Vegas. We will still be receiving emails, but if there is a delay in response, this is why"

If they're saying those seatposts are backordered, my guess is that they are backordered.