Yep, annoying when a buyer uses feedback as a messaging board.
Do remember leaving a reply no matter how annoying and unfair the negative was, speaks volumes about you as a seller. If you were a buyer reading your replies would it put you off buying from that seller?
Those negatives are too old now to change but before leaving any reply, try and remedy the matter with a buyer and yes I agree it can be through gritted teeth, but most can be pacified and then a feedback revision can be sent.
@essential-sunglasses