OP - I suggest you seek feedback removal - I reported this buyer and have had a response from ebay customer support - extract below -

I've checked the information you sent us and I can confirm that xx user id xx left inappropriate Feedback. In our policy, we don't allow members to use Feedback extortion in order to receive a refund.

Threatening to leave negative Feedback, demanding the withdrawal of Feedback, or demanding a refund in exchange for not leaving a Negative Feedback is considered Feedback extortion.

I know that you are really disappointed with the way your buyer acted. I am glad to inform you that I have taken appropriate action on xxuseridxx account based on our policies. For privacy reasons, we can't discuss the exact details of the investigation.

I am attaching a link that you can review to learn more about our Feedback Abuse and Removal policy. Please go to:

http://pages.ebay.com.au/help/policies/feedback-abuse.html

http://help.ebay.com.au/Help/Policies/Feedback/Extortion

Furthermore, for us to be able to remove the feedback, please write to us using the account truebluecosmetics12.