When you call, and if the answering machine comes on, just leave a message.
Some guy (forgot his name) always, I mean always, calls me back and answers my question.
However, if you're going to ask them about the status of your application, they will just tell you that they're loaded with applications to look at and the admissions committee reviews the applications on a "rolling" basis.
So if you've submitted your application early, and had everything in by the end of September, you should be hearing from Tufts shortly.