quickymart:
A unified billing system would not be easy to implement. Remember there are a plethora of legacy companies, all with their own distinctive billing platforms.
I agree with the comments re ditching the overseas call centre however - having that is just a waste of time and completely negating any possible savings that might be being made from having it outsourced.
I can think of 5 that need to be merged: VF/ihug, VF Mobile, TelstraClear, WxC, Sky (assuming its approved)