Is he lying or telling the truth?

Ever buy anything from amazon.com marketplace? I do it all the time to buy like-new used textbooks. I also sell a lot of textbooks on there and have never had a problem. Well, 3 weeks ago I ordered an anesthesia text from a private seller and never got it. I emailed the seller a week ago and never heard back. So today, I emailed amazon.com and told them what happened and that I wanted my $50 back. I also left the seller negative feedback with scathing comments like, "unprofessional" and "doesn't return email". Well, tonight, I got an email from him. He was apologetic, saying that he can't be responsible for the post office losing books and that he never got an email from me. In fact, he didn't even know there was a problem until he saw his negative feedback from me. He asked me to remove the feed back since he refunded my money today.

Now I feel bad. Maybe he really did send the book and it got lost. Maybe it was delivered to the wrong address. Maybe someone stole it off my front porch. I was out of town for a week, but my neighbor came by and checked my mail everyday. I doubt she did anything with it. She works at Dillard's. What's she going to do with an anesthesia text?

Still, even if he did mail it. I find it weird that the book got lost AND he didn't get the email I sent him. Since he refunded my money quickly, I removed the negative feedback.

So my question is this: Is he lying about ever sending the book and is now trying to save face or did it get lost?