Our team has been using FreeScout for the past month or so and it has been great! We came from no helpdesk solution since we have a Free/Open Source requirement for our project stack.
What People Say About FreeScout
This is only great open source alternative for HelpScout. Using this for events and collaboration between teams for small projects. Indeed its very good option compared to paid services if you want to keep an archive of your data forever and prevent data access by service provider.