He’s taking the pee here really.
Firstly that a bagain for wheels with tyres. I haven’t even been able to find a 9mm qr 26″ back wheel for that cost that’s even half decent.
Secondly, the tyres are pictured on the rims, with mud on and you list they go up tubeless and have tubeless valves.
Thirdly, if there’s a tiny bit of residue in the tyres, what difference does that actually make.
I’d think of ‘hardly used’ as having been on the bike and used a few times – so definitely not ‘as new’ – so wouldn’t expect the item to be absolutely pristine – just not very worn.
On the point above, I agree that the listing comes across as primarily for the wheels, with tyres thrown in. Therefore a complaint about a slightly dirty inside of a tyre is irrelevant to me.
Who knows which side eBay will fall on if a case is opened – I’ve not got involved in one at all despite having sold quite a lot of stuff. Maybe I’ve just been lucky.
I think I’d not offer any kind of refund and tell him your description was fair and the tyres were just thrown in additionally so you can’t see an issue.
Then see what happens.