Some energy auto-switching services are comparing less than 15 out of around 70 energy suppliers, despite claiming to cover most of the market, according to Citizens Advice.
As a result, some customers are paying £70 a year more than if they switched themselves, the report found.
The report also found that some auto-switchers were providing inaccurate or unclear information, for example some were listing energy firms who have gone out of business.
Citizens Advice said it believes the problem is that third party intermediaries in the energy market, such as auto-switchers and price comparison websites, are not currently regulated.
The current lack of regulation of third-party intermediaries means that consumers can face problems that are difficult to resolve, such as auto-switchers failing to cancel a switch, leaving customers facing exit fees. Some bill-splitting companies fail to pass on communications from suppliers, leaving customers in unexpected debt.
Dame Gillian Guy, chief executive of Citizens Advice, said: “The lack of regulation leaves people facing potentially serious problems and a lengthy and difficult path to resolving them.
“The government has an opportunity in the upcoming energy white paper to fix current problems and make sure the right consumer protections are in place.”
Don’t miss the Utilities & Telecoms Stage at the Credit Summit 2020 on March 19.