Whether you’re out for the day or are off for the week, the first rule of an out of office voicemail greeting is: let callers know when you’ll be back! You’ll save them the frustration of continuing to call and yourself the hassle of listening to redundant voicemails. It’s also a good idea to set the expectation of whether you are answering messages while you’re away, and who they can reach for assistance in your absence.
The longer it gets, the more likely your potential client will hang up because they are annoyed.

Hello, it’s obvious you have bad timing, because nobody is home. Please leave your name, telephone number, and a brief message in a voice similar to mine, and your call will be returned as soon as humanly possible.
6. The Referral. A referral sales voicemail works when you are referred to a client by a third party. If you are reaching out to a prospect you haven’t spoken with, you might start by mentioning that you were referred before clearly stating the intention of your voicemail message.