The bottom line is that a business’s situation is likely to change often and rapidly, each of which need a unique and applicable voicemail greeting to cover the circumstances and timeline. For example, callers shouldn’t reach a business-as-usual voicemail, and therefore expect a return call within the business day, if the subject they’re calling is out on vacation for two weeks. Such a lack of communication is a recipe to lose that caller’s trust and tarnish the brand’s reputation.
Education Details: Users and departments can customize their extensions with their choice of music, messages, and voicemail greetings. Keep your callers on the line with professionally recorded messages on hold. Keep callers engaged by answering frequently asked questions, such as business hours, locations, or directions.

You might also consider giving them the option to skip your voicemail message completely by pressing another key (again, check with IT). You also want to make callers aware what you will return their call, instead of telling them that you will try to return their call--and let them know when you are likely to do it, if possible. If necessary, provide additional or emergency information in your voicemail greetings. My dentist, for example, lists his cell phone number for emergencies.
Keep in mind that to enjoy the full benefits of your professional greeting system, you must routinely check and delete messages. If your voicemail fills up, you won’t be able to receive new messages, meaning your customers will become frustrated.