He never read listing before buying things, buy wrong item, his own mistake,Conclusive fact.
After seller nicely explain to him. He immediately making threat to leave negative feedback and will never do business with that seller again.
Oh,please go ahead,our team will help seller get fair judgement. Don't be funny，you think any sellers would want any future business from people like you? A coward who dare not admit his mistakes, arrogant and rude after the fault is revealed.

You can leave unfair negative feedback on seller. But how about we Tell the world your negative character?