The title pretty much says it all. I had subsidised my only shipping line, so they would build some more ships. Well they did, they had 4, totalling 100k in tonnage. And then, for no reason or listed Event, they all started bombarding whatever planet they were in orbit of. They're still listed as a shipping company on that screen, but on the system map they are red dots, moving apparently randomly between my colonies.
I also can't work out how to get my battlegroup to actually attack them.
Any help/advice on what I can do would be appreciated. Normally I would reload a previous save, but that doesn't seem to be an option in this game.