What would you do

if there were two other people out there with very similar e-mail addresses to yours, and you sometimes received e-mails intended for one of those two other people, and your attempts to communicate the error to the senders of the e-mails were sometimes met with gratitude, sometimes with rudeness, but usually wholly ignored?

I don't even know what the real e-mail addresses of these people are, else I'd go to them directly and say, "Hey, you might want to emphasize that minor difference between your address and, say, somebody else's, when you share it with others."

Some of the people I notify continue to make the same mistake (and sometimes with important things to say, like, "I've bought the tickets; meet us at the station at 3"), and I've already been yelled at for being insensitive (by replying bluntly to everyone on the CC list). In the last four years, two, maybe three people have written back thanking me for catching their mistake. I'm getting pretty tired of setting myself up for disappointment, but I worry that ignoring these e-mails could create conflict and misunderstanding in the lives of others.

What responsibility do I have to any of them?