If your buyer had opened a return request using the reason 'Arrived damaged' then eBay would have just refunded the buyer at no cost to you and without any need for the buyer to actually return anything. Unfortunately, now that you have refunded yourself there is probably not much you can do other than appeal to eBay. You can't do anything with Evri as contractually eBay is the deemed sender not you.
Packlink no longer has any involvement with Simple Delivery. They were only involved at the pilot stage.