If a phone rings once and then goes to voicemail or rings only briefly, it usually means either that your call is blocked or that the phone is not receiving calls at all. If the phone rings five times and then voicemail picks up, it's more likely that the person on the other end simply isn't picking up the call.
Slydial is an app that is available for both iOS and Android. Free accounts are available but they require you to listen to an ad before making your call.

Changes can be made to voicemail settings on the phone through the voicemail options audio menu only after the initial voicemail password has been set up in Account Manager, Work for Desktop, or Virtual Office Online.
The telephone systems have the feature named as Voicemail. VoIP is the best example of it. When a receiver is unable to pick up the phone, then the caller can leave the voice message on the receiver’s phone. In older telephonic machines, such messages were stored as a voice message directly, and the receiver can hear them later. In modern telephone systems, such info is being stored on the server of the service provider in the user’s mailbox. It is similar to email in which the messages are saved in the form of audio instead of text.