iPod Nano 7th Gen won't play audiobooks

Hello all-

I have a 7th Gen iPod Nano that won't play an audio book that I have played there a number of times before. It just all the sudden quit working. It's only the one audiobook and it gets 7:45 in and then stops playing. I have deleted and turned off the Nano and then turned back on and re-synched. I have updated the software and re-synched, and now I'm at a loss. Maybe the file got corrupted somehow? Can you get a refund for these? Any ideas on what to do?

Thanks so much in advance for any advice.