I would applaud you sending a letter, but honestly this company might not even receive mail at their box or just outright discard items coming from unknown parties. I feel like you'd be putting some effort into this and they wouldn't even notice or read your letter.

These sorts of trolls tend to operate with a minimal amount of staffing since they're usually subsidiary spin off companies (so nothing but bare bones is allocated in terms of payroll) and since patent trolling is such a gamble (if you're trolling 200 patents with the expectation of getting one or two hits then you should try and minimize costs)