Campaigners have praised the firm behind the National Lottery after it quietly abandoned an 0844 phone line. But they have warned that too many councils are still using the expensive numbers.

A year ago, Guardian Money highlighted how Camelot had expanded its use of 0844 phone lines, to the huge annoyance of its customers and partner retailers. In some cases, consumers instructed to call the lottery firm to claim their winnings were spending more on the calls, which cost up to £2.60 a minute, than they had won. At the time, David Hickson of the Fair Telecoms Campaign said companies that continued to use 084 or 087 numbers were being “greedy and foolish”.

Now the National Lottery operator Camelot has replaced the phone lines with standard 03 numbers that are free to call from most calls packages.

Hickson, who praised Camelot for seeing sense, warned this week that too many other businesses – notably airlines and councils – are still using the 0844 numbers, which can cost mobile users in particular a fortune to call.

Campaigners have fought a long battle to persuade companies to stop using 084 and other revenue-sharing numbers. The success of the “Say no to 0870” website campaign was in part due to consumers’ huge annoyance at the use of such numbers by firms, government agencies and doctors’ surgeries.

The Consumer Contracts Regulations (2013), which came into force in June 2014, outlaw companies from using telephone numbers that charge existing customers more than the “basic rate” charged to geographic-rate numbers that are prefixed 01, 02 and 03. Such numbers are free to call for any telecoms users with an inclusive calls package.

“The fight goes on,” said Hickson, who says 50 councils still use 084 and 087 numbers. There is a list of the offending councils on his website. “These lines are used for payment of council tax, council house rent, overpayment recovery and other items such as parking fines,” he said.