Looking for opinions on this knife trade situation

So I’m in a difficult situation

An individual traded me for a knife

He had a socom elite I really wanted like new in box

I had a socom elite he wanted that I told him I carried a few times and had sent him photos of prior to the trade

He messaged me today and told me the knife was not in adequate condition

He showed a scratch in the dlc, some rust near the hinge and a few other miscellaneous things

This surprised me because I hadn’t been aware of that and the knife had hardly ever been used

He discussed options and he said he wanted us the basically ship both knives back to each other

I said I didn’t want to do that because, well… this socom is pretty badass

I asked if I could give him some more cash

He asked for 100 which would mean he got the knife I traded him for 250 bucks. Kinda insane to me because it retails for 475.

I came up with what I thought was a fair solution

I pay the difference and have him sell my knife for me

My thoughts were he could move my knife faster than I would be able to

He said I’d have to pay him 100 to sell my knife because it would take up time and resources.

I feel like he’s being unreasonable, but would like to get some options before I do anything.