The basic rule of thumb is that callers should hear one of two things when they first connect with your voicemail — either an apology for not being able to answer the call or a “thank you” for having called. You can do both if you prefer, but keep it short and to the point.
“Good afternoon. You have reached the office of [your name]. I will be out of the office beginning on [date] and will be returning on [date]. Please leave a brief message with your contact information, and I’ll be sure to get back to you as soon as I return on [date]. If this is an emergency or you need to speak with someone before I return, please contact [name of colleague/supervisor], [their job title], at [their phone number].”

“Thanks for calling the desk of (insert your name) at (insert your company name). I’m either on a call or away from my desk but if you leave your name, phone number, and the reason for calling, I’ll return your call as soon as possible. Thank You.”
Timing is everything. The moment you receive the lead alert is the best time to make the follow-up call. If you call them days later, your chances of getting them on the phone are greatly diminished. By calling them right away, you’ll talk to more leads which will inevitably boosts sales. Role-play your voicemail scripts so you sound like you’re making your 20th call, not your 1st. Ask your friends and colleagues for honest feedback on your voicemail scripts. Continually review what’s working and what isn’t -- there’s always room for improvement. If you have the lead’s email address, follow up with an email, and let them know in the voicemail you’re going to do so. If you don’t have an email, let them know you’ll follow up with a text.