include your phone number twice in the message. that way, they don't have to rewind/replay. or not as much, anyways.
"hi, this is foo from bar baz and co, 111-222-3456, looking to talk to you about our monkey and the banana inventory issues we've been having. my number again: 111-222-3456."
no subject
"hi, this is foo from bar baz and co, 111-222-3456, looking to talk to you about our monkey and the banana inventory issues we've been having. my number again: 111-222-3456."