8.) Benvenuti al Servizio Assistenza della John Doe. Purtroppo, tutte le linee sono occupate al momento. Si prega di lasciare un messaggio dopo il segnale con il vostro nome e numero di telefono. Vi richiameremo al più presto possibile. Vi auguriamo una buona giornata.
38. Thanks for calling [company name]. We’re unable to take your call right now, but leave your details and we’ll call you right back.

You could add the words "After-Hours Service" or "After-Hours Line" after the company's name. That way there's no concern over whether it is indeed a number that reaches a real person who will return their call during non-business hours. It's a way to let them know they're on the right track. If that makes sense. :)
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.