An item was broken while in delivery?

I sent a person an unscratched disk, but today the person is emailing me saying that "The game arrived today, the game disc has several scratches, your auction description stated that the disc has no scratches at all, i bought this game to sell it to a local games shop, the game value will decrease because of those scratches, I'm willing to keep the game if you give me a 5 pounds partial refund as a compensation for the scratched game disc." Shall i refund him? It was not my fault