Voice mail for STC pre-paid

Hi everyone!  I'm trying to set up voice mail on my STC pre-paid phone.  I called the number and set up the greeting but when I call the mobile phone it does not play my recorded greeting or allow someone to leave a message.  Any ideas how to enable this?

There are three different options for using the voice mail:
1-When you don't answer: Dial (*61*1111#) To cancel (#61#)
2-When you're on the line: Dial (*67*1111#) To cancel (#67#)
3-To divert all calls to voice mail: Dial (*21*1111#) To cancel(#21#)

Thank you very much.