Ann: Norwood Launches World Voicemail, page-7

WhatsApp doesn't have any phone call (international voice phone system) functionality. It's a very different sort of tool. I totally agree that apps like WhatsApp are eating into the viability and profitability of 'old school' voice based services like the ones Norwood are pushing, but they certainly don't completely replace them. If someone you don't already know wants to contact you, they still need to know your phone number to add you to WhatsApp before they can send a audio message. At that point, a phone call is just as simple as a message on WhatsApp is.