EDF and Utilita have been named the worst energy suppliers for customer service by Citizens Advice.
The consumer body said customer service ratings across the sector were among the lowest ever, reporting record numbers of households asking for help with energy problems between January and March.
Research from the charity has found that more than five million people in Britain live in households with debts to their supplier.
Average customer ratings for companies were down 10.5% compared to the same period in 2021, and had leveled off since late 2023.
The charity said customer service standards have still not returned to pre-energy crisis levels, leaving many more people needing support from their suppliers with issues such as debt and forced installation of pre-payment meters.
Citizens Advice is calling for the introduction of a “Consumer Duty” – a new set of rules that would give Ofgem stronger powers to hold companies to account and end “years of poor customer service”.
In the latest rankings, Ecotricity tops the rankings, followed by Outfox the Market, Ovo Energy and Utility Warehouse.
Also in the top 10, E (Gas and Electricity) was at number five, followed by E.ON, ScottishPower, Good Energy, Rebel Energy and Octopus Energy.
In the bottom third, Co-Operative Energy was at number 11 with a score of 2.52, followed by Boost Power and So Energy. British Gas is at number 14 with a two-star rating of 2.39.
EDF, one of the highest scoring suppliers this time last year, has fallen to the bottom after average call wait times rose from just under a minute to more than five minutes in less than a year.
Utilita has improved since the last quarter, but remains one of the lowest rated suppliers.
Citizens Advice said there was an improvement in average call waiting times following new guidance from Ofgem in December.
However, companies performed poorly in their ability to resolve customer complaints, driving down overall ratings.
Citizens Advice CEO Dame Clare Moriarty said: “When millions are struggling to afford basic needs, it is completely unacceptable that energy companies are failing to provide the right support to their customers.
“Citizens Advice has long called for Ofgem to be given stronger powers to hold suppliers to account on customer service. This should include tackling the backlog of complaints before next winter.
“The news that bills will fall slightly from July will come as cold comfort to the record numbers seeking help from our advisers. The next government must introduce more targeted energy bill support for those who struggle to keep the lights on or cook a hot meal.”
An EDF spokeswoman said: “We recognize that our response times are not meeting the high standards we have set for ourselves and we are committed to doing better and returning to the market-leading service our customers expect.
“We have recruited and trained more people across our Sunderland, Brighton and Exeter offices and are nearing the end of a complex transfer of our residential clients to a new IT system, which will see more clients contacting us as we navigate this process. ”
Utilita said: “We shouldn’t underestimate how smart consumers are today. They will realize that the Star Rating contradicts other market-wide supplier ratings – including those from Ofgem, Trustpilot and Which? – where Utilita consistently performs well.
“As such, we look forward to an ongoing dialogue to bridge the gap between the perception provided by the Citizens Advice Star Rating and the reality provided by other rankings.”