Returns and similar things on ebay or in person are an interesting thing.
I botched one early on a cancelled sale, was a bit snippy in an email to someone who could have been an interesting contact later.
From there I started waiting to respond if I was mad.
Most of the ebay complaints were ones that were entirely valid, and I think I surprised the handful of people who did have complaints. Fortunately I mostly sold cheap stuff so it was pretty easy to surprise people with a good response. I did generally ask questions though.
Like one guy said a bicycle helmet he'd bought was cracked. It was brand new, so that was a bit surprising. Thinking it was a crack caused in shipping I asked if he could send a pic of he crack. Nope, it had a molding around the edge, and under that was multiple cracks. checked my other ones, and they were all cracked
Obviously refunded the whole thing, shipping included and thanked him for pointing it out as I'd never thought of checking under the mouding.
He asked about returning it and I didn't want it back. It was plain white, so i suggested he let a local artist or grafitti person go crazy on it then turning it in to a lamp or wall art. Which he seemed to like.