We were typing our letters at the same time.
No need to go into any details as to why, simply put, it's an as-is where-is sale. If the buyer doesn't understand that, and really believes that he is entitled to a refund, then he is clueless.
Yeah but yours is better
If I was OP, I would just email that unless anyone else can think of a reason not to, other than " you don't have to" which I think is a weak reason to do anything...
Surely sending that can't open you to litigation or anything?