Thank you BB. Yes, I will give it one more try, it won’t hurt. Reporting the seller might make a difference, ebay told me that the free returns + having a clean record were both required for the seller to withhold part of the refund. They were selling another similar item at the same time that I’m fairly sure was also fake (same item, different stone), so I asked CS if the other buyer realized it was fake and filed a claim would that allow me to appeal and possibly win. The rep said maybe, but there was some convoluted complication, namely that it would all have to happen with 30 days (of the purchase ?).
Update on my counterfeit purchase with only partial refund issued! Wow, the seller just relisted the other item similar to the one I purchased that was authenticated as counterfeit (same model, different color). Now it says “Van Cleef Style” and it is thousands less, of course. She has not posted the one I purchased again, but it may be coming. I was planning to try to call ebay CS again in the morning to see if this makes a difference in the verdict in my situation. The last conversation with CS went similar to the other ones, the representative said that since the seller had a good history on her account that they could not require her to refund me the difference in the partial refund she gave me, and when I asked if it would make a difference if in the future the other item similar to mine was also return for being counterfeit, and the representative said possibly, but only if it was within 30 days of the purchase. I just checked, and today is 31 days after my purchase and she just listed it! I’m sure she knew I would be checking for it. I did leave her negative feedback, which I have not done before, I made it very general and just said “unfortunately, the item was counterfeit”. I checked and she now has 100% positive feedback and my feedback was removed!