I've got a ported Telkom number that I'm using. However, when I'm unavailable the message from the system mentions the SIP number, which can be confusing to someone that dialed my "Telkom" number.

In another thread it is mentioned to set up a custom message to avoid using the automated message. I have tried all four options, "record a message for when you are unavailable", "record a message for when you are busy", "record your name" and "record your temporary greeting". None of these seem to change the message being played, so I'm still getting the automated message mentioning the SIP number. Am I missing something? How do I change the message?