If you didn’t save your work, then I’m not sure what can be done if you don’t have an automatic external save. If you just accidentally deleted chapters, then you can:
Go into InkStone and click on the Stories icon on the side column, you will see all your works. Click the illuminated Explore icon on the work you lost chapters in. You should see Draft, Published, and Trash. Click the Trash one, and you should see your lost chapters.
I hope this helped🤞🏻🤞🏻🤞🏻 ☮️