Hi @Ethio_Giz ,
Welcome to the community!
In the event that you're pertaining to TPG Mobile Voicemail, we did an article related to this that you may find helpful please see link below.
For ADSL/NBN/TPG FTTB Home phone service.
TPG does not offer a messagebank or a voicemail but you may simply use a phone handset with a built in answering machine.
Let us know should your require further assistance.
How can I change a voicemail greeting once after the first set up.
I have tried to use different methods to change the greeting voice message.