In those cases, you might like to save that voicemail somewhere other than your phone for safekeeping or sharing.
It is no surprise that your actual voice mail greeting must be delivered in the same way: Professional, clear, brief, and to the point. In a previous blog, "Marketing Messages on Your Cell Say You Mean Business," some techniques for making a professional voice mail greeting were discussed. There are many similarities between leaving a voice mail, and producing a voice mail greeting. You want your callers and receivers to hear a confident and professional person on the other end delivering a coherent message. You should introduce yourself to a prospective client in a personal way. An email doesn't generate much discussion, nor does it necessarily show you went the extra mile in contacting the client. Generating conversation. A professional, well conveyed voice message shows the voice mail receiver that you are confident and well-spoken, and that there is a person behind the message. Emails can be prepared, edited, and revised unlike voice mail messages An email or email chain thread is documentation of a conversation that can easily be referenced In an email you can include a phone number, address, website, etc that may be hard to remember or record through voice mail communication Emails can be forwarded, CC'ed, and blasted.

Avoid telling your prospect what to do. You'll make returning your call seem like a chore or, worse, a demand. This should feel like a mutually beneficial relationship -- one in which each party wants to call the other back -- unprompted.
This scenario piques your prospect's interest by teasing information. But it's only effective when your prospect actually cares about the info. If you say, "Next time we talk, I'd love to tell you more about our latest award for customer satisfaction," they probably (read: definitely) won't care.