If you want to make a user stop following you, just follow the next steps: 

  1. Access your Profile from the bottom bar of the app;

  2. Underneath your username, tapthe "Followers" button;

  3. Next to the users name, you can tap the "Remove" button;

  4. A pop-up will appear for you to confirm the action.

The user you remove will not be notified of the action.