Professional
(always unanswered unless a recognised number)

"You've reached Gabriel West. Unfortunately, I'm unavailable at the moment, but leave your name and a contact method and I'll get back to you as soon as I'm able."
Personal

"Hi, it's Gabriel! I can't get to my phone right now, but leave me a message and I'll get back to you. Cheers!"
(always unanswered unless a recognised number)

"You've reached Gabriel West. Unfortunately, I'm unavailable at the moment, but leave your name and a contact method and I'll get back to you as soon as I'm able."
Personal

"Hi, it's Gabriel! I can't get to my phone right now, but leave me a message and I'll get back to you. Cheers!"