Optus is looking to improve its standing among customers by abolishing breakage fees and reducing bill shock, as it deals with lower revenues.
The telco lost 38,000 customers during the three months to September, taking its total number of mobile customers to just under 9.5 million.
Rival Telstra has continued to grow its market share, and has 15.3 million customer.
Optus' revenue fell five per cent during the quarter to $2.12 billion, mostly due to its removal of breakage fees and simplification of international roaming charges to avoid bill shock.
But cost cutting measures ensured the company lifted its net profit to $218 million in the three months to September, up from $164 million in the same period in 2012.
Chief executive Kevin Russell said Optus was losing revenue due to mandated reductions in termination fees, but was also foregoing some revenue to improve its standing among customers.
"We are taking the difficult decisions to forego short term revenues which are unsustainable, with a view to establishing stronger medium term revenue growth and improving customer trust," he said.
There had been a 36 per cent decline in complaints in the past 12 months, thanks in part to the changes, Mr Russell said.
"We feel as if we are in a good place for the next calendar year and financial year in terms of being able to compete strongly for market share without necessarily being overly aggressive on just price," he said.
