I got this email too. I think I have about 600 Amazon ebooks...and all but two of them were freebies. I imagine they're sending the email to anyone who has any ebooks, but I'd be really surprised if it turns out either of the two books I bought actually get a refund.
I doubt either one of them was an Agency book. I remember I bought one by accident (thought it was free, but it wasn't). The other one was a $1.99 book I couldn't find anywhere else.