I want removed,
As has been explained, what the buyer has said does not break eBay's rules on leaving feedbck. eBay won't get involved in whether the buyer's comments are correct, this is between you and the buyer.
The buyer said your game didn't work. If they are now saying that it does work, it's up to them to revise the feedback they lef you. To do this, you need to send them a feedback revision request, see: https://www.ebay.com/help/selling/leaving-feedback-buyers/disputing-feedback-received?id=4102#sectio...
You have to send the request within 30 days of receiving the feedback, and the buyer will have 10 days to revise it.