This seems to have all been done wrong!
1. A seller, whether independent, business, consignment, hobbyist, or whatever is required to know items are authentic prior to listing. And if she doesn't know, she's supposed to find out before listing.
2. Thus (possible) claims of ignorance or trust of a consignee regarding authenticity doesn't fly. It's the seller's account and reputation on the line and again, she should have verified.
3. Why did you go to Lollipuff? Did the seller demand a letter of non-authenticity? If so, IMO, as a matter of ethics, she should reimburse that too though you can't force it.
4. Why did she issue a partial refund?
At this point, because the whole transaction is so convoluted, I'd suggest you open SNAD for fake and presumably she'll agree to the return and refund and you'll get a prepaid shipping label.
Once shipped and delivery is proven, you can go to ebay with the tracking info if she doesn't issue the balance of the refund.
ETA: IMO, videotaping is a waste of time and ebay doesn't consider video evidence. I've never videotaped any purchase, return or sale and haven't ever wished I had.