Around 3.8 million energy customers were overcharged a total of £270 million due to billing errors last year.
That’s according to a report by uSwitch, which estimates it cost each household on average £72.
Around 9% of them are yet to receive any money back from their supplier and 12% waited more than two months before the issue was resolved.
More than a third – 36% – of consumers whose supplier made a mistake said the wrong tariff or product details were applied. Around 31% said their suppliers applied incorrect fees, 27% said they used the wrong meters and 24% said companies set inaccurate direct debit amounts.
Claire Osborne, Commercial Development Manager at uSwitch said: “Consumers have a right to expect correct bills. It’s unacceptable in this day and age that customers are picking up the cost of suppliers’ mistakes. Households are already trying to cope with the high cost of energy and can’t afford the additional cost of simple blunders.”