Why is that? Can you explain a bit further?

Hi Ladies and Gents, Been lurking around for a while but really need to pick your brains now... It's quite a long one, so bear with me. Over a month ago, I sold a ring to a guy in Belgium via eBay. Everything went well, he paid by PayPal, I posted the ring out to him, he received it. I then received an Email from him saying the ring wasn't as described. After checking it out, I realised that he was right and that I had actually made a mistake in the listing (copied the details off the H-Samual website, but used a similar rings details) Oops! No problem I thought. I offered him a full refund on receipt of the ring back in England and a full apology. Weeks passed by and I still hadn't received the ring back, so the buyer opened a PayPal dispute as he hadn't received a refund. After weeks of communication, it turns out that the buyer hadn't insured the ring on it's return journey back to England, but because he provided a valid tracking number, he has won the case and Paypal have refunded his money. The tracking number he provided is still showing as 'in dispatching in foreign country' on the Belgium post offices website, not 'delivered' but apparently that is all PayPal require. I am now left without a ring and without my money. I have contacted Paypal and Royal Mail and neither of the are interested. The buyer won't even contact his postal company as he didn't insure the parcel, so they wont care either. Something about this whole situation seems grossly unfair. Surely it was the buyers responsibility to ensure the item arrived back to me safe, and if he chose not insure the parcel, shouldn't he be the one liable for the loss? I'm at a loss at the minute and don't know which direction to turn in... If anyone can give me any advice, it would be greatly appreciated. Cheers,