"Thank you for your thoughts on this matter, I didn't read them. Here is a boilerplate statement espousing all the great things about this bill that you specifically criticized in your message to me. Please don't reach out again."
To be fair, the same shit happens when you call them. Some intern answers and you don't even get the platitudes. You might just be a tally mark on a list if they feel like it.
I like emailing my senator/CP because it does create a paper trail. One day maybe I'll run against them and read all the emails I sent them, in public.