Jeannie, that bag looks completely authentic to me. Some minor changes occured with the 2006 season: a thicker, heavier lining in some bags, stiffer leather, and a larger Chloe font on the leather lock wrap. Anyone unfamiliar with these changes could easily mistake an authentic Paddington for a fake. I purchased two Whiskey bags from NM - the second one looked exactly like yours while the first one was super slouchy, pebbly and very saturated with color. I returned the second one because I thought it could be mistaken for a fake.
Find out exactly why this dude character deems your bag a fake. Is she the Chloe fairy? The Paddington Queen? Phoebe's little elf?? I think the members of this forum who own multiple bags are perfectly capable of authenticating a fake bag from photos, and I am eager to see if anyone disagrees with me that your bag is the real deal.
I'm eager to hear the reasons why. Unfortunately, without being able to contact the seller for authentification in the form of a receipt, you probably have no recourse and are stuck with the bag.