Just my opinion: Keep the return policy, and if it bugs you, avoid looking at that number on your report. (If this proves a major need, I could write an Excel macro to handle that for a small fee.
Seriously, I think doing a disservice to millions of shoppers just because a small handful might abuse the privilege is just wrong on several levels.
When I got the first return on my 99 cent short work, it put a frown on my face, but I quickly got over it when I realized that >99% of people who bought my work were keeping it, and not because they were stuck with it. They could have returned it, and didn't. That made me feel pretty darned good.
(The second return I got put a frown on my face until I realized that it was me...I hit the buy button on my Kindle accidentally while showing it to someone, and immediately clicked the "I bought this by mistake" link. Maybe that's what happened in the OP's case too. Who knows?)