Email makes it too easy to avoid the important questions and also makes it impossible to read into the response. With a call, you can almost always pin them down or at least find out what they do not want to answer honestly. My guess is that is why they will not return their phone calls too.
We are apt to shut our eyes against a painful truth... For my part, I am willing to know the whole truth; to know the worst; and to provide for it. --Patrick Henry, Patriot and Hero of the American Revolution