How do I do this please ?
Best answer by Mohammed
Welcome to the iD Community!
It's really easy to increase the time before going to voicemail.
We've got lots of information about Voicemail here
The bit you're looking for is;
How do I increase/decrease the time before a call goes to voicemail?
When receiving a call, your mobile is automatically set to ring for 30 seconds before it's diverted voicemail. However you have the ability to change this at any time to a choice of five-second intervals, ranging from 5 to 30 seconds. All you need to do is enter **61*123** followed by the number of seconds you'd like your phone to ring for, then # and call. So, if for example, you'd like your phone to ring for 20 seconds, you'd need to dial **61*123**20# and press call. Once you've done this, a message will pop up on your screen confirming the update.
Hope this helps!