After creating, the Voicemail Greeting, you can test it by calling to your number from another phone, and see if it is playing correctly or not. Open the Phone App. On the lower screen, tap on the Voicemail option. Select Custom, with this option, you can record the personal voicemail greeting on the iPhone. Tap Record, to start recording the voicemail greeting message on the iPhone. Greeting samples are given in this article below, Once you are done with recording, tap Play to listen. Lastly, if everything is alright, and custom voicemail recording is perfect, then tap Save.
Rollover Hunting is a feature that is managed by the Account Manager or Phone Manager. It allows incoming calls to your primary phone line to roll over to the next available line and, if al l lines are busy or not answered, the call can roll over to voicemail. It will hunt through all lines in the group once to find an idle line. You can configure multiple hunt groups and the number of rings before the call is routed to the next li ne. Each hunt group must have a minimum of two lines and a unique primary number. There are three hunt sequence options:

Start Skype and choose Tools→Options→Calls→Voicemail from the main menu.Put a checkmark in front of Send unanswered calls to voicemail.Just click the Record button (the green button with the triangle) and speak the Voicemail greeting you want callers to hear.Click the Stop button (the red button with the dot) when you're finished recording.Click the Replay button (the red button with the backward arrow) to listen to the message you just recorded.When you're satisfied that you recorded the perfect message, click Save.See More....
Why Your Business Should Have a Business Voicemail Greeting. A voicemail greeting is a simple message that plays before callers leave a message. It may play either when you don’t answer or if your phone is off. A professional greeting may encourage people to leave messages, which in turn makes it easier for you to get back in touch.