I had a smilar problem. This is what they told me by email to do.
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- In your internet browser, go to
www.kobobooks.com
- Sign in with your email and password.
- Go to your "I'm Reading" list. Select "Purchased." You'll see all of the books you have purchased on Kobo.
- Select each book you want to undelete.
- Choose "bookmark"
- When asked, "Do you want to bookmark page 1?", choose "Yes".
- Repeat for any other books you've mistakenly deleted.