My T's answering machine has the standard 'if this is a life threatening emergency call 911'. I've never called her wanting her to call me back to talk on the phone. I hate talking on the phone so at this point I can't imagine wanting that! The one time I called to ask for an extra session she called back within a couple hours and squeezed me in to her schedule the next day. That built my trust up a lot. The only other times I've called are due to scheduling issues and she always has called back that day or within 24 hours.

Personally, I wouldn't want to exchange emails with my T. It is to easy for things to get misunderstood via email.