I think you missed the point. Heytel uses your internet connection (free WiFi in many places), and not your phone plan. For example, people I know are travelling to China in April, and their research shows that texts will be 25c to receive and 75c to send ($A), voicemail far more as it is a phone call to send and receive. However, one data service allowing 5 devices to connect (which they all nedd for email connectivity anyway) allows 5 users to send and recieve Heytel messages effectively free as it's using the data.
So no, it's not voicemail as people know it at all. It can also be used effectively to hold a 'walkie-talkie' type conversation, again effectively at no cost.
Originally Posted by
mixture
An example of a solution to a problem that never existed.
What you are describing there, in other words, is voicemail. A standard part of pretty much all mobile tariffs whether PAYG or contract.