Some Genesis customers are in for an unexpected windfall after the company committed to refunding more than one-million to business clients it overcharged

The company will refund more than 14-hundred customers who overpaid a total of 1.1 million dollars between 2014 and 2020 after the Commerce Commission found it is likely to have breached the Fair Trading Act.

More than 13-hundred other customers were overcharged a total of 2.4 million dollars, but won't be chased.

Genesis alerted the Commerce Commission to the issue in July last year.

The Commerce Commission has issued Genesis a formal warning over its actions, saying customers wouldn't have been able to easily identify the error.