Was he right to give negative feedback eBay?

I created a listing on my iPad for a game for Xbox 360 on eBay and was going to upload it but decided I would do it at another time. A few weeks passed and I happened to go on eBay to look for a DVD I wanted. I noticed I had about 5 messages in my inbox. They were from a guy who had won and paid for the game I thought I hadn't put for sale. I was surprised to say the least as I was certain that I hadn't put the game for sale. I messaged him immediately and said that I hadn't meant to put it for sale and that I had no recollection of uploading the listing. I offered to send the game with a full refund for posting and packaging and he accepted. Of course I understand that he would have been annoyed with what seemed to him like being annoyed and I can see why he gave negative feedback but at the same time I do feel like it was a little uncalled for as well, given that I had 100% + feedback with over 40 sales. Also the fact that the game and the P+P combined only came to £2.99 hardly meant that he would be massively out of pocket. Also from the point of when the listing ended to when I messaged him back was about 3 weeks.

I know it's not the biggest thing in the world but it's just a little frustrating when I have over 40 sales with %100 and now there's a mark on my score.

Is there anything I can do or should I just accept that it's just life!

Thanks

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