Does anyone know how to contact ebay to resolve negative feedback?

I have just sold a pair of mk4 rear lights. The items auction description clearly stated postage to united kingdom only by royal mail first class.

However, someone in france bid on them. So i explained about the postage situation and offered him a full refund.
He is now up in arms saying that he doesnt want a refund, and wants not only the item sent but some form of compensation for me offering a refund on an item he bought.