although the buyer will have lost what she was
expecting to have in her possession/collection -
this is sad on her part.

But this is a "semi-quick" simple solution.

I've had good experiences with Nick for my very
tiny & cheap orders. But as everyone has
mentioned, mistakes happen.

I've had a shipping mistake in the past that the
postal worker placed the incorrect zip code that I
tried to mail....mistaking one of my "7"s for a
"9" so it got shipped to a totally different state
and was either lost or in limbo for a month. I
refunded the money and a week later it turned up
on her doorstep, so that story ended semi-happy
through all the trouble and filing claims...
But the lesson is the same as here and to check
your postal receipts! I've learned my lesson from
this.

Stuff happens.