Extending ring tone

My phone only rings 3 times before going to voicemail

JohnD17 Try the following - dial **61*121*11*XX# and press the call button, replacing "XX" with your desired time in seconds (e.g., 30 for maximum time).

Hasn't worked
All on get after typing and calling is
MMI Code
Call forwarding when no reply

Registration was successful

Then
Ok

Sorry to hear you're still having issues JohnD17. Please get in contact with customer support for more help.