My name is***** am sorry to hear that you are having this issue.
I will be glad to assist you with this.
Try this please> press and hold the power button down for 20 seconds, then power back on. Then go to your Home screen. Tap the Sync tile.
After you sync your Kobo eReader, your book will be added to your Kobo eReader’s Home screen and your Library. To start reading, just tap on the book cover.
Let me know how it goes please.