Redmine (http://www.redmine.org/) is an open source software for tracking your customer issues, planning your work. It can be configured also as an agile tool using appropriate plugins (redmine agile).
Proposed list of plugins
- Redmine email fetcher (https://github.com/luismaia/redmine_email_fetcher), you can use this plugin to fetch pop3 or imap email in order to automatically create issues from emails.
- Redmine agile, (https://www.redmine.org/plugins/redmine_agile)
- Redmine A1 theme, (http://www.redminecrm.com/pages/a1-theme)