Unfortunately, you strike the occasional buyer like that. It's partly due to the attitude shown by one or two sellers who have written in reply to this post. One bad experience leads the buyer to adopt a 'me vs them' attitude.

When you strike one of those, you can write to eBay customer service, though it's unliely they'll be able to help. So you just have to take it with a grain of salt. No point in stressing out over it. Just remember the 99% of buyers who are polite and reasonable and never let yourself - and other sellers - down by losing your temper - it's just not worth it.