“Greetings! You’ve reached [your name and position]’s voicemail. I am away from my phone or [other important and expected job function]. Please leave me your name, telephone number, and a short message. I’ll get back to you as soon as I can, typically within [reasonable timeframe, like 12 or 24 hours].” How do I record my company voicemail?
True emergencies - such as extraordinary weather - should be addressed in your voicemail if it impacts your business. Thank you for calling the Carona Surf Shop. We are currently closed due to the inclement weather. Our normal business hours are Monday through Saturday, 10 am to 9 pm. Please visit www.caronasurfshop.com to order merchandise and to check our schedule during the hurricane.

I have a confession to make: I haven't recorded a new voicemail greeting in nearly a decade. Since then, I've (hopefully) become more articulate, poised, and self-assured. But hear my voicemail recording, and you'd think I was still new to the work world, a little unsure of myself — and probably not an authority.
To clear any customers doubts or expectations, make sure to mention on your voicemail when you’ll be available. Don’t say that you will “try” to return their call. Instead, offer them a realistic timeframe in which they can expect their call to be returned, so they know what to expect - whether it will take you 24 hours or a week to get back to them. This will eliminate your customer’s worries about your timeliness and encourage them to wait for your reply instead of heading over to your competitors.