On September 16th, I received an email with the above title, saying that my payment method had been declined.
I contacted my bank, and they said they saw two charges (my subscription order had been split in two for shipping) and that both had been approved. (I checked again today, and both charges have moved from pending to "real" as of the 17th.)
I called Paizo next and spoke to Virginia (I believe), and she said she saw nothing wrong with either part of my order, suggesting that perhaps the system sent the email as a glitch.
As of today, however, when shipping was supposed to be complete, I haven't received a shipment email for the Ambush Sites Multi-Pack flip mat, nor is the PDF in my downloads.
I'm not in any huge hurry for the maps (I'd be much more frantic if it had been my AP installment stuck somewhere), but could you take a look at this again? It appears that I've been charged for the map pack, but it hasn't actually shipped.