Hello there,
I'm a VoIP expert and linux system administrator with extensive experience setting up VoIP solutions using Freepbx/asterisk. I work on Freepbx almost on a daily basis, either setting up new solutions, offering supports or testing out features. So, setting up a trunk and outgoing routes is something I do all the time, so I know exactly what to check in order to fix the issue.
It would be great to discuss with you before getting started. I'll also be ready to show POC before we can get started.
Bertrand Ndakena