Whether it’s an out-of-stock product, a canceled event, or social media snafu, there are times when your business may see an influx of frustrated callers. While it is important to address their concerns head-on, you may not be able to answer each call as it’s received. Make sure you use best practices for dealing with angry customers, and that your voicemail greeting sets the appropriate tone. Avoid defensive language, validate their concerns, and keep them informed as to how you are handling the situation.
How to Leave a Voicemail. Leave a voicemail by using your normal tone of voice and keeping your message short, between 20-30 seconds. Start the voicemail with information that's relevant to the contact and ask questions that are tailored to them.

Cell phone voicemail greetings are generally more personal and casual than office phones. Consider a greeting like “Hello, you’ve reached [your name]’s cell phone. I can’t take your call at the moment, but if you leave a brief message, I’ll get back to you as quickly as possible.”
Not many might consider it, but your business voicemail greeting is probably more important than you think. Now, we probably all hate recording those generic voicemail greetings at home or on our cell phones. But when it comes to our business – a generic, lifeless robotic greeting probably just won’t cut it. And thanks to the software that comes with your business VoIP solution, it is easier than ever to change your greetings on the fly.