Best of luck sorting.I Stopped selling on Ebay after a similar thing.
All those mentioning insurance that is not always straightforward, I sent an expensive component to be anodized and after a while it never came back so tried ringing the company,number not recognized,bit of searching found out they had gone bust 2 days before I actually sent it(had used for years), got onto Royal Fail and asked for proof of delivery as I had paid for insurance up to £500, they produced the guys signature to say he had it , i said how could you have delivered it they don`t exist , “we have delivered it to his forwarding address” I thought great where is it “We are not allowed to disclose this , if we did we would be breaching his rights”.But you have not delivered it to where I asked , yes but we have delivered it to who you asked at his new address.They will wriggle out of anything. Never saw it / him again just had to machine a new component at a cost of about £500