Ok, I got an update. The manager told me that she talked to her boss, who talked to Corporate. Corporate wished to convey to me that Saks would never "knowingly" sell a counterfeit, but since I'm not "happy" with the item, they'll take it back. However, the Saks card that I purchased the bag with is closed, so I was offered a store credit, to Off 5th ONLY, no regular Saks.
I called the credit card customer service, and they said a refund can be issued to a closed card, and I'll get a refund check in about 30 days. So I'm going to opt for that instead. I don't think I can shop at Off 5th anymore.