Ebuyer did not read the description ...

[IamnotStiller]

Have recently sold a trainset plus extra tracks (as two items). As I did not have time to set up and test I put this into the description i.e. used a .... ago, worked then but have not used recently so maybe best for spares. Sold both items to the same person who is now saying it does not work and he does not want either of the items. WWYD?

Tell him that the item description made it very clear that it had not been used recently, and made no claims as to whether or not the set worked. He should have read the description properly - and if what he wanted was a working trainset, then he could easily have contacted you to ask whether or not the set worked.

It is his liability - you were honest in your description.