Vodafone has been fined $350,000 for making false representations in invoices sent to customers.
The telco pleaded guilty to 14 charges under the Fair Trading Act and was fined today in the Auckland District Court.
The Fair Trading Act breaches took place between 2012 and 2018 and resulted in Vodafone customers overpaying $285,000.
Vodafone chief executive Jason Paris said: "Every customer deserves an accurate bill every month. We clearly fell well short of that in this instance, and for that I apologise. If you get it wrong, you should put your hand up, acknowledge it, and make it right."
Vodafone said that, on average, affected customers were over-charged by $9.70 each.