The irony behind buying fake blades, but having a conscious over ripping off the Chinese store is rather amusing.
This is my take on it.....
If you bought a new one for £250 - You wouldn't accept any "discount" for a defect - You'd want a brand new one with no defects.
As you paid a very small sum, I can assume you don't have an issue with buying fake blades (this train of thought has been discussed before), so yeah, I'd take the refund and not give it a second thought.
i don't see a real difference between selling this mizutani and selling say the new donic ovtcharov which is a copy of the viscaria or the tibhar unlimited cca which is a copy of the maze.
even the stiga carbonado has very big construction similarities with a viscaria.
there comes a point where everything is pretty much a copy of everything else, like music lol.
the only difference is donic has tons of money to invest in marketing while a small chinese factory has none.
as for me ripping the store off, it doesn't matter if I'm dealing with the devil himself, there's no reason to do something I don't think is right.