Just a quick update. We decided to purchase a license for IPB and have laid the foundation for the message board itself. We are now looking for contributors/freelancers to help integrate invoicing into the site. If anyone would be interested in helping out please reach out to either myself or BitCryptex. Thank you!
In case u have not made a payment yet, u could try
https://www.discourse.org/We considered Discourse but ultimately decided to go with IPB for practical reasons. That could always change though.