Read perldoc perlform on how "@" characters are handled. To get a literal "@" on a line, you have to do:

From: Me < Me@example.com >
            "@"
[download]

This is because "@" is taken to be an argument substitution whether or not it is backslashed. I also wonder why you're using formats when your not substituting anything (I assume your example just doesn't reflect that part yet).

blakem is right though, a here-doc might be more appropriate for this, depending on the actual body of your email, of course.