The lawyer who represents the public at the Energy and Utilities Board says Irving Oil Ltd. cannot retroactively change prices on bills a Saint John customer paid years ago.

"It's ridiculous," said Heather Black.

"It's just like anybody going to the store and buying their groceries and then getting a call from the grocery store saying we're going to charge you more."

Black was reacting to news a Saint John woman has been offered $178.20 by Irving Oil to repay $547.36 it over billed her for heating oil.

The company acknowledges it charged Eileen Fudge more than New Brunswick's maximum legal price for oil on 27 deliveries between 2007 and 2015, but says it also charged her less than maximum prices dozens of other times.

It has since raised those prices to the maximum retroactively and told the woman's family it was deducting the new charges from what it owes her.

Black says there is nothing in New Brunswick's petroleum pricing law, or law generally, that supports the practice of raising prices retroactively.

"The charges were made at a particular point in time and going back and changing that even in the context of offering a refund seems a little strange to me," said Black.

"It doesn't follow what anyone would expect from the [Petroleum Product Pricing] Act or anywhere else in law."

Irving Oil heating oil billing practices are currently being investigated by the New Brunswick Energy and Utilities Board

Black says Irving Oil is within it rights to make any offer it wants to the Fudge family, but she says if the EUB confirms any customer was charged more than the maximum price for heating oil on any delivery, those customers should be given all of their money back.

"I would hope if the investigation does reach that conclusion that these customers would receive refunds," she says.