What you have pointed out to me is that you are probably pretty difficult to deal with. So, yes you probably argued with the guy, which was one of his complaints with you.
As for your shipped prices, while they may be a little high, I didn't really see an issue with it since it is listed in the auction.
Lastly, the reason for asking if you ran a business was to give the chance to say if you were the person directly dealing with this guy. Your Ebay number is huge which could mean that if you have a business there are others that help you out and it was possible that someone else had argued with the buyer. Although now, it appears that was probably you.
I sold Final Fantasy VII, Poke'mon Yellow and X-Men: COTA to raregamergirl and she paid very quickly and the transaction went smoothly without any problems at all.
And yes she is a girl gamer.