I think the emails are legal (enough) documents here. Start to collect those and also the attempts when and how you tried to contact him, e.g. time of (failed)

I think the emails are legal (enough) documents here. Start to collect those and also the attempts when and how you tried to contact him, e.g. time of (failed) phone calls. That will build a stronger case. You probably need patience though. Starting proceedings to get him out of the company without compensation or chance to review documents might be seen as hostile. Good luck. And good luck on the business itself, may it grow regardless.