Was the "project founder" related to the company that sold you the commercial add-on? If not, why should he support it, unless of course there is some commercial relationship between the open source project and the company selling the add-on?
Yes, his company is the one that made the add-on; it was their first commercial product atop the open source project. Today they're a nice fat funded company, but then, they had little revenue, which really put me off.
