To uninstall fail2ban just follow these instructions.
Uninstall just fail2ban
sudo apt-get remove fail2ban
This will remove just the fail2ban package itself.
Uninstall fail2ban and its dependencies
sudo apt-get remove –auto-remove fail2ban
This will remove the fail2ban package and any other dependant packages which are no longer needed.
Purging your config/data too
If you also want to delete your local/config files for fail2ban then this will work.
Note! Purged config/data can not be restored by reinstalling the package.
sudo apt-get purge fail2ban
Or you can use this command
sudo apt-get purge –auto-remove fail2ban
Maintainer Ubuntu Developers
Home page http://www.fail2ban.org
Description ban hosts that cause multiple authentication errors