That's totally Bad!!
I had one customer leave negative feedback with me, calling me a scammer as well.
I had this negative feedback taken off from eBay because I was able to prove what had happened.
eBay CAN and WILL take that negative feedback off, but not through email. What I have found, is that when you email them, you basically get bounced back and forth between different Customer Service Reps.
Ring them.!! And don't let them off the phone until they fully understand what has happened. You may need to send them your emails between you and the horrible buyer.
Phone number is: 866-877-3229, or 866-540-3229 and 877-322-9081 are alternate numbers
Hope this helps

Michelle Haku