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

Package Data
Package fail2ban
Version 0.9.1-1
Maintainer Ubuntu Developers
Home page http://www.fail2ban.org
Description ban hosts that cause multiple authentication errors
Distro ubuntu
Release vivid
Repo universe
Section universe/net