restore audiobook

Do you have a question about audiobooks ? If it's no longer on your phone then if you have a copy of it on your computer's iTunes (if you do then it will be in the Books part of your library) then you can sync it back to your phone. If you haven't got a copy of it anywhere (it's not on your backup of your downloads ?), and it's still in your country's store, then as they are currently a one-time only download from the store you will need to try contacting iTunes Support and see if they will grant you a re-download : http://www.apple.com/support/itunes/contact/

this is a widley know problem with ios7.01, please go to: http://www.apple.com/feedback/iphone.html and ask for this to be fixed