I’d be a bit annoyed at that, but as said above, eBay’s fees are probably the culprit, happens quiet a lot, I’ve certainly had it on more than 1 occasion (although not with bikes) in fact I once won a whacker plate for £20 spoke to they guy who seemed a bit disappointed but ok, was driving from North Wales to Portsmouth and item was located in central London, so a pretty big diversion, arrived at house to be told “someone’s just stolen it” I was really not very happy. After all that I left bad feedback (all factual just starring what had happened) as it had been a huge inconvenience to me, 24hrs later he called eBay and complained about it and the feedback was removed!!!
As such I don’t ever leave feedback anymore as its a waste of time and I tend not to use eBay that much these days