[BNM] [OT] extending ringing time on Virgin mobile phones

[Rebekah]

I've just got a Virgin mobile account and my phone annoyingly goes to
voicemail after 4 rings which means I never get to it in time unless it's in
my hand. Virgin want 10p a minute to tell me what to do, tight gits, can
anyone advice me on how to extend ringing time to say, 6 or 8 rings please?

Cheers

rebeKah