How do you tell if a salvattore ferragamo wallet is fake?

My husband recently purchased a Salvatore Ferragamo Bag for me in Shanghai Duty Free shop, but when I saw this bag , my first impression was this is not a genuine bag. Knowing Duty Free shops carry only Genuine products, we are disappointed my husband paid for a price of a genuine Ferragamo bag & got a fake bag !!! Here are some of my comments why I insists that the bag is not GENUINE: Underneath or back portion of the bag strap in the body area is very sticky which is very unusual for a genuine bag. Inner cloth inside the bag has different material (rough) compare to the original Ferragamo Embossed text in the Leather Tag inside the bag is different compare to the genuine bag. Bag strap have only one thread in the center compared to the Genuine which has 2 threads on both sides all the way down. Hope you can help me regarding my concerns & check this particular shop located in Terminal 2 Duty Free Airport in Shanghai