Non-followers are accounts you follow that don’t follow you back.
Use this feature to view all these accounts and Unfollow or Whitelist them. You also have the option of directly tweeting out to these accounts by using the Reply button.
Where do I find the Non Followers for my Twitter account?
You'll find your Non Followers feature within the Manage tab on Crowdfire. The Manage tab is situated on the top bar (web app) or the bottom bar (phone app)
You can also sort this list by Oldest or Newest first from the top right.