I’m not in the US so, YMMV, but in France, I subscribed a "legal insurance". It will cover enough fees to at least give you enough insight about what is happen

I’m not in the US so, YMMV, but in France, I subscribed a "legal insurance". It will cover enough fees to at least give you enough insight about what is happening, if you should defend your case, if you are faulty or if you should just ignore the threat. Also, even if our judiciary system isn’t perfect, I doubt you will find a judge that wouldn’t be comprehensive of a random being attacked by a corporation. Especially if there is no obvious malicious intent or personal benefit, you only risk some symbolic fine and the order to stop. So, I would probably ask for judiciary advice and either ignore or comply to the troll.