Unhappy buyer .What to do ???

Just wanting sum advise here .I sold a third memeber to a fellow member across the country a few months ago.This was a spooled 8.75 chunk that i had made a handfull of low 7 second passes with in my car.The gear ratio was too low for my set up ,so i went back to my old chunk.

I made it very clear in my ad the the chunk was used for about 10 passes ,but was a rebuilt unit prior to that,and was in good working order in my car when i pulled it back out.

I got a pm today after 2 months of silence from the buyer.He told me that he had it checked out and under the opinion of the guy that checked it out ,it wasnt "broke in properly" and the gears are no good ,even though they look good to the eye.

He is asking me for an adjustment in the form of $$ .I dont feel im in the wrong and i described it as best i could in my ad ,and it was as i decribed it .I dont want members thinking im shadey ,but i dont feel i wronged him .What would you do ???

http://www.forabodiesonly.com/mopar/showthread.php?t=172218 Here is a link to my actual ad