What to do about negative feedback?

Looking at my smiley faces, I see I have a red angry face with a very rude comment.  This took me by great surprise as I had emailed the seller at the time explaining and apologizing my computer had crashed - took some frustrating day's at getting the computer fixed and then re loading and the passwords being a problem to get back in to everything. I paid, emailed and no problems by email with the seller. But I see this angry and rude comment not to deal with me?  The comment was back on the 10th of April, I can't even remember what the product was, I have been busy on trade me and weird must have bought a bit over time from this person as I had them as my Fav. How do you reply to this red face reply back as because as time goes on the red faces stay but not the comments, they get lost in the feed. I have been with Trade Me for years. Once I sold 2 rings, got them mixed up sending the more expensive one to the wrong person and on the pre text they had said they had paid, but they hadnt, then left me a red face on saying it was wrong - but when asking for them to return it or pay, they didnt, they re listed it selling it themselves. The matter was dealt with the Police but there red face remained all these years. Another gave a yuck face as it was latterly just a few days to get back to her so she could collect - and pay on collection - it was just a few days, and I explained that my parent had died, the reason why. She had no problem at the time, yet after she gave the silly face. This face thing is very unfair. I have a very good record and its being wrecked by a few being B's. What do you do? I have another problem too which will also post - I made 1 listing a week back and it sold, I have no idea why even though it sold, the auction kept going and someone else won too a few hours later - I managed to stop it. While the first person who actually won is fine, the other now has emailed wanting to purchase.