When you leave a voicemail do not use your full name because that immediately raises a red flat that you are a salesperson making a cold call. Instead, say your first name only followed by your company name. This will make your customer feel that you are much more familiar with each other than you really are. Saying your last name would defeat the whole purpose of demonstrating familiarity.
As mentioned above, alerting callers that they won’t be getting an immediate call back is of upmost importance for an entity’s reputation and a caller’s satisfaction.

I have a confession to make: I haven’t recorded a new voicemail greeting since 2014. In the past four years, I (hopefully) have 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. Obviously I need toupdate it. And if you haven’t changed your voicemail greeting in over a year, you’re likely in the same boat. After all, a professional voicemail recording boosts your credibility, makes you seem more competent, and encourages whoever’s listening to it to continue the relationship. A relatively unprofessional one — like mine, for instance — does the opposite: It encourages prospects, recruiters, and potential connections to run in the other direction. With that in mind, I’ve written 18 unique voicemail greetings for every situation. Pick your favorite, practice a few times, then record your new voicemail.
10. "Hello, you've reached [X company]. We can't take your call right now, but please leave your name, contact information, and reason for reaching out, and one of our team members will be in touch within 24 hours."