Ebay tires sold now stress

Hello, so I have the following problem: I sold on ebay tyres from a Simson (Metzeler racing tires) I put them in as used and only had a picture of the running surface in it and nothing else written about it because you have seen the important running surface on the picture. I also ruled out warranty and withdrawal, so the buyer agreed by his bid. Jetz suddenly reported and he suddenly noticed that the tyres were 16year old. he wants his money back. 21.Oct they were sold and so today on 20.11.2011 he noticed that. He asks for the withdrawal. Should I worry about this or can I say NO? thank you already here the auction http://cgi.ebay.de/ws/eBayISAPI.dll?… or article number 270832194441