It definitely sounds like he is trying it on. For me I would probably steer clear of selling hardware to anyone in another country these days due to not being able to do as much if things like this happen.

You do have to be very careful in item descriptions and try to give as much clear information as possible. I think you really should have stated in the auction that "the card will only fit in a towered A1200 and will not fit into a standard desktop A1200 without modification." That would have covered you against the problems you now face. Sadly there isn't much you can do at this late stage.

The other bad thing is that ebay/paypal can just refund the buyer from your paypal account without warning and you then end up minus that amount from your account, and can end up without the item or the money. This happened to my wife a couple of years ago. She sold a Nokia mobile to someone for £50 and the guy was pressuring her to post it to him as quickly as possible, so she posted it with the last post on Saturday at the delivery office, so could not get proof of posting. He then claimed the phone never arrived and paypal just refunded him the money from her paypal account and she wasn't able to do anything about it. She she lost the phone and the money. Bad!

Ebay is not good these days when a buyer is dishonest as sellers just don't have any powers to fight their side of any arguments and disputes.