If it is stated in the auction that the cartridge is a reproduction, then the buyer has no reason to complain. Even if they did just skim the auction and didn’t read the description, common sense would dictate that a Coke Wins selling at $20 or $30 with a buy it now is not an original.
Hypothetically speaking, even supposing a seller isn’t clear in their description or isn’t being totally honest, I think that once the money is refunded and the whole thing is resolved, there is no reason to give negative feedback.
The buyer has no basis to give negative feedback here. In this situation, the seller did everything right. In fact, they showed great customer service by responding and refunding the money so quickly.