This is exactly why I had an LLM customize the letter as I said in my other comment; I've had a similar response from another of my representatives. It might not help much if they're filtering based on where the email is coming from, but on the off chance that they are filtering based on identical content, changing the content might make a difference. With LLMs, the effort needed to customize the content has gone down significantly (otherwise, I would agree with the more cynical commentators that such letters are a waste of time and energy).