At some point in your eBay selling life, one of your customers is going to send you a complaint. As long as you respond to it properly, however, its easy to keep a complaint from turning into a crisis.
Respond Immediately and Grovellingly.
Someone might complain to you directly, or they might do it through eBay. Whatever happens, you need to email them immediately. Heres a template to use:
I have just received your complaint and I would like to say that I am very sorry you arent satisfied. If you would like, I can send you a [replacement/refund] for the item, as part of my no questions asked guarantee. I apologise again for our mistake.
Whatever you do, dont start making excuses for yourself. Oh, sorry, I didnt get around to posting it yet because Ive been busy at work and Im going on holiday next week no-one cares. If the buyer isnt satisfied, then you screwed up, and you need to apologise repeatedly and do everything you can to make them happy again. Besides, is it really worth your time to go through eBays long-winded dispute process when all its going to do is alienate your customers?
This an attitude that will give you a massive...