If your ebook hasn't sold on Kindle in 30 days or more it's probably because of one of the following.
Your book's title isn't interesting to your target audience.
Your book doesn't have the proper tags (keywords) for your target audience.
Your description isn't descriptive enough and/or has grammar and spelling errors.
Your books cover doesn't work for your genre and target audience.
The preview section may need to be improved.
Schedule your webinar on how to greatly improve what's been mentioned above by visiting the Kindle Publishing Webinar.