I won't ask for revision as I said before, coz  hopefully my 'polite and truthful reply' will speak for me.

What you need to remember is that with the way the feedback system and DSR system works is if you receive too many non positive feedback comments and/or low DSR's then eBay can restrict you as a seller.

Although you consider your reply will speak for itself eBay will not take that into consideration if for some reason restrictions are placed on your ability to sell.

As you have refunded the buyers payment, to protect yourself as a seller, I would email the buyer, apologise to them for not being happy with their purchase and ask if they would consider revising the feedback for you.

You have offered great customer service, which is part of the whole eBay buyer experience, so it would be nice to see the buyer acknowledge the service you offered in a positive way.