Okay, I'm EXTREMELY slow

First of all, I bought a Rex Stout book that I already had. (Can I help it if the covers of all the Nero Wolfe books look more or less alike?) So I decided to put it up for sale on Amazon. After quite some time, Three for the Chair finally sold. I went to ship it today, and realized that I had put the wrong book up for sale. The book of which I had two copies was Three Doors to Death.

Can I help it if the titles of all the Nero Wolfe books sound more or less alike?

*facepalm*