I am really sorry to hear about your experience.
I have no idea, based on your post, what your demeanor was when the cop came up to you. What I can tell you is there are some cops out there, who, it's not a good idea to cross.
It's yes sir, no sir, kind of thing.
Your story sounds really bizarre to me.
You could attempt to fight this, but in my humble little opinion, you'd be burning cash and time up for no reason.
But, use the search function on this site, or pick up a phonebook, or whatever, and start dialing lawyers. Many times, they will talk to you for a little bit for free.
If they think they can make money on it, they will take your case. If you can't find a lawyer interested in it, you got your answer right there. And you will know.