As DG said, definitely send photos, because a common thing for sellers is to say they broke something, when they either didn't get enough at auction, or they realise afterwards they could have got a lot more as a BIN than they listed. The buyer will be unserstandably upset. Don't be at all surprised, even if you do everything right, that they give you neutral or negative feedback. If they do, cop it on the chin and maybe even put a polite reply apologising (that's what I did when I had a similar thing happen). Hopefully it won't come to that and the buyer is OK. Don't worry if they don't accept a cancellation. It will time out in 10 days automatically.