Damning research by comparison site uSwitch has revealed that 3.8 million customers have received incorrect bills from their supplier leading to them being overcharged.

The most common supplier error was that the tariff or product details were wrong which resulted in 36% of overcharged customers being affected.

The other supplier errors highlighted and the percentage of overcharged customers affected were:

• Incorrect fee applied: 31%
• Charge different to meter reading provided: 27%
• Direct Debit was wrong: 24%
• Bill muddled up with somebody else’s: 23%
• Charged twice for the same product: 21%
• The bill didn’t add up correctly: 19%
• Special offer or discount wasn’t applied: 14%

Of those who had overpaid, uSwitch found nearly a fifth waited between one and two months before their billing issue was resolved while 12% waited over two months.

However, 9% who were overcharged as a result of their supplier making a mistake have yet to receive their money back.

‘Consumers have a right to expect correct bills’

Claire Osborne, energy expert at uSwitch.com, said: “Accurate bills are essential if consumers stand any hope of taking control of their energy use and spend. Recent upgrades by some suppliers to billing systems have resulted in teething problems, but today’s figures show there’s still more for the industry to do.

She added customers should always check bills carefully, and speak to your supplier as soon as possible if you think you’ve been short-changed.

It’s also best to provide up-to-date meter readings to avoid estimated bills and to check that the figure has been used by the supplier.

If you’re confused by your energy bill, see uSwitch’s energy bills explained video.