I had an issue last year with ebay/hermes, gear was showing on hermes tracking as delivered, but no pod or delivery picture.
Seller literally went "shown as delivered, not our problem, go whistle for a refund or replacement", hermes wasn't much better initially with a robot system that went round in circles & choked every time it got to the non existent proof of delivery, initially ended up jumping on the local delivery guy, who then gave me his ops managers name, she was more help & established the item had not got past the senders depot, & maybe not even collected by hermes ?, so was it the sender pulling a fast one, possibly ?.
Even tracking down the European ceo of hermes email got an agreement that they would now consider it lost, but still ebay dragged their heels settling the claim, & PayPal weren't much better as the pod crap automatically closed down any attempt at a claim.
What a cluster fuck, & trying to get any of them to talk to each other was like herding cats, very stupid cats lol.
Only way it was resolved was my inability to not quit (which I think they were hoping for), it was only a £30 transaction, so while I wasn't prepared to devote much of my time, every week or so I'd fire off a pre-pasted email or make them call me with a couple of button pushes & then send them off to chase each others tails lol.