This makes absolutely no sense!

Something tells me either he was setting you up, or he ****** up and was too embarrassed to let anyone know he couldn't block a punch.

This will get thrown out in court in 2 seconds. Just start looking for a new instructor and don't think too much about it.

Clearly, your sensei didn't wax on and wax off enough.

That's his fault. You shouldn't be banned for his idiocy. He made the mistake so it's all on him.

Time to start teaching yourself, start advertising about how you are so good your former sensei could not even block you... Make sure you name him properly so all his students will transfer to you.

I'm going to start by saying that if the instructor told you to throw a punch at him, and you did what he asked, when he asked, how he asked, then he has no room to complain and nobody will take him seriously. HOWEVER... If you didn't do what he asked, how he asked and when he asked then he has every right to throw you out. If I ask someone to throw a slow punch to my face and instead they try to kick me in the groin ... well, that's crossing the line from a co-operative training exercise to someone just outright assaulting me. And the instructor might not be prepared for something like that. That doesn't mean they're bad at martial arts, it just means they're talking to the class and expecting a slow and easy punch where they can show the technique in slow motion while they explain what's going on to everyone else. Even expert martial artists can get sucker punched. I'm not saying that's what happened, but I have seen it happen more than once. Step back and honestly ask yourself: "Did I do what was asked, how it was asked for and when it was asked for?" If you threw a fast punch when he asked for a slow, or a belly punch when he asked for a shoulder punch, or did anything other than what was requested, then you need to be honest with yourself and admit that you owe him an apology. If the instructor didn't specify what was required, or if you delivered what was required, then you're in the clear.

This sounds like a solid case of student teaches instructor lol

At first I thought you had thrown a cup of juice at him, which would have made getting the police involved a bit silly.

The police won't care, OP, it's a contact sport. Time for a new dojo.