You mean this tutorial?
How do I use my Voicemail?
I followed that and it worked fine but you have to read and follow it carefully.
Do you get any error messages?
Where are you seeing any reference to an MMI number?
USSD/MMI numbers are normally short codes used to configure things or get info from the network.
Please describe in more detail the specific problem(s) that you are having.
Hope this helps.
