Originally posted by Wheatfield Have him send you a picture of the lens including the serial number.
Or, have him return the lens to you (at his expense) so that you can compare serial numbers.
If the numbers match, refund his money, if they don't, then let him pay return postage if he wants his lens back.
Originally posted by stevebrot Wheatfield's suggestion is a good one.
As Wasser pointed out, damage during shipping is a different issue. As a buyer, it is my practice to photograph the box and the un-boxing for anything that I buy as documentation that damage did not occur in transit. Have the buyer provide proof that the item was well-packed and that the packaging was intact and in good order.
Steve
Personal experience: A determined crook will always win.
The unfortunate truth is, you can ask for all the Serial Number photos you want; you could have taken all the pictures you wanted before shipping, and the buyer could still say, "You didn't ship me the lens you photographed."
IOW, the buyer could have a damaged copy of the lens you sold, fake photos of "removing it from the box," show the damaged lens as the one "you sent," and there is absolutely no way to prove the buyer is lying and you aren't (short of digging into EXIF time-of-photos in jpeg's). Even using EXIF you can't prove anything - you just make the buyer's story look more suspect.
A determined crook will always win at this game. The only question is how determined the buyer is, and how many hurdles you throw up to make the buyer jump over.
Personally, I'd offer the buyer $17.50 and move on.