The Australian Communications and Media Authority has recommended that telcos be banned from using confusing words in advertising materials, after an 18-month inquiry into customer service.

The results released last month were in light of mobile phone subscribers signing up for mobile plans with wrong assumptions due to confusing words used in advertisements.

ACMA is the federal regulator for the telecommunications industry.

Fairfax Media's The Age on Wednesday reported about Tamara Hetaraka, who subscribed to a 12-month $49-cap mobile phone plan inclusive of a Nokia X8 smartphone with Vodafone. A year later, she says she exceeded the $49 cap almost every month, with the worst costing her an extra $350.

''[My mother's] phone did the same thing too, so none of us understood what was going on. But it cost more to end the contract than to just pay it,'' Tamara said.

The Age noted that 17-year-old Tamara signed up for a plan she did not properly understand and continued with it because she was unable to use Vodafone's self-help services as well as its online billing services.

Tamara recalled she was charged 60 cents every time she called Vodafone for balance inquiry, and sometimes she would be told she had credit available only to find out a huge bill at the end of the month.

Tamara said the name of the product - a $49 cap - made her assume that she could not go over the ''cap,'' as $49 was a set limit.

''They have the prepaid cap where you can't go over and they have the postpaid cap where you can. I thought it would be the same,'' she said.

Tamara's experience is not unique, according to The Age.

To their credit, the big mobile carriers are sending text alerts when users are running out of free calls, texts or data. Many already offer online self-service facilities.

Still, Teresa Corbin, chief executive of the Australian Communications Consumer Action Network, says Australian telcos are not putting as much effort into customer service as those overseas.

''The reality is that, yes, telecommunications equipment is complex. However, the actual plans and products you design around that equipment and those services do not have to be complex,'' she said.