I recently sold a camera ( 40d) to a person. This is a camera which I had no problems with when I used it....but I hadn't used it for about 10 months so it sat in my bag. My primary cameras are my Mark 3 and Mark 2N. My daughter used it a couple times to go out with me and shoot some nature stuff. It was cleaned and calibrated about 1.5 years ago with my 17-55 by Canon. So I sell it and transaction was fine. Now 6 weeks later, he informs me that the camera is front focusing and accusing me of selling a bad camera.....and he is contacting me to " make the situation right!" He states he sent it to Canon and the work will cost $200...which is the standard Canon cleaning and calibration charge! What would you do in this situation. I certainly wish he had notified me before 6 weeks which raises some concerns to me. On the other hand , I would never wish anyone to be unhappy with a transaction I made. Again, what would you do??