My job is provide what I promise, not rationalize whether the reason for the purchase makes sense. What I did was examine the complaint. I looked at the sale from my customer's viewpoint to find errors in my presentation, and fixed it. I also wrote back to this person with my explanation of what I thought I was communicating in my previous message and to inform them of a complete refund of their money. You mean you sold something.
Life is too short as it is.
It doesn't improve if you hold onto every penny you come across. Besides, that complaint DID make me change the approach I had been taking to sell guaranteed traffic, and the process I went through probably improved my offer and the satisfaction of future buyers, and that was worth more than this one sale. So, the next time you get hammered for something you have sold, don't ignore it. Don't get angry. Fix it, and learn from it.