Just a personal example of how it worked, once. I'm not at all implying that it will work this way every time. I had called a number of times, never contacting the appropriate person, but leaving a message each time. I received no responses. To show how important the concern, I don't even remember what it was about. But I eventually sent an email outlining the problem and detailing the failed call-backs. Within the hour of sending the email I received a telephone call that resolved the concern. That particular time, and for that particular problem, the email worked better than the phone calls. Anecdotal evidence is suspect, at best, but my experience has been that emails generate responses where phone calls are not always successful.