When you delete an audiobook from your Kobo app, you can get it back by going to your account archive.
- Go to kobo.com
- Sign in to your account.
- Select My Account at the top of the screen.
- Select My Books.
- Select Archive near the top of the screen.
- You'll see a list of items that you've deleted from your Kobo account.
- Find the audiobook you want to restore, and click the More icon under 'Actions'.
- Select Restore to Library.