Wait a sec! You are NOT at fault, unless it's for being a bit too trusting of a less-than-honest seller.
The seller was totally at fault since it's a seller's responsibility to know that her items are authentic before listing them. And unless she bought from a legitimate and authorized retailer and unless she's expert in a brand, it's always a good idea to verify authenticity just to be sure.
Unfortunately, now that the listing was removed, you won't be able to leave feedback, but this is my opinion. I'm not a huge fan of dinging a seller's feedback when a seller does the right thing but since your seller didn't respond appropriately, you were forced to file a dispute and she still didn't issue the refund and instead, you had to have ebay act on your behalf, this seller (IMO) would rightly have earned negative feedback.
One would like to think that your seller,
kim37005 would have learned from this experience.
ETA: CORRECTION: The seller to avoid is
Member id kim73005. (You'd copied her ID incorrectly in your original authentication request here: #
7684.)
http://forum.purseblog.com/coach-shopping/authenticate-this-coach-763164-513.html#post24188047
Seller to avoid is
kim73005 as a result of this post: