Consumer Focus says complaints against 'Big Six' suppliers have risen by 26% despite their promises to rebuild trust

The Big Six energy firms were under fire again today for allegedly treating customers with "contempt" after a 26% rise in complaints over the last three months despite promising to rebuild trust.

The surge in problems was reported by the watchdog Consumer Focus as the power sector has been attacked for poor service, high prices and soaring executive pay. The consumer group singled out EDF Energy, RWE's npower and E.ON for particular criticism as they had performed notably worse than in previous periods.

Adam Scorer, director of external affairs at Consumer Focus, said: "Energy companies have repeatedly said they want to rebuild consumer trust. Good customer service and complaints handling are key ingredients to building consumer trust but suppliers still have a long way to go.

"Complaints about EDF Energy over the summer have had a catastrophic impact on its rating. While system changes inevitably cause disruption to customers, this must be minimised. Its current complaints performance is unacceptable and the company must take further steps to tackle this."

John Robertson, a Labour MP and campaigner on the issue of fuel poverty, was much harsher in his criticism. "What we are seeing is the subjugation of energy customers by the Big Six. These energy barons are treating energy customers like medieval serfs.

"And as snow is about to fall and temperatures drop, you would expect energy companies would be doing all they can to please its customers. However, these figures show if anything they are treating them with contempt," he said.

The dismal performance by the Big Six – with the only bright spot being a better performance from ScottishPower – arrives as the industry is facing calls from some politicians for a complete restructuring.

EDF, a French firm that generates most power using nuclear stations, accepted that its position was undermined by the introduction of a new billing system that left customers confused and then angry when they could not get through on the telephone.

Despite 700 more staff being brought in, there was a need for more, it admitted. "As soon as delays occurred, we recruited an additional 400 service staff, which naturally took time to become effective and we slowed down our plan to move customers on to the new system to ensure service levels were stabilised and restored."

SSE kept its top five-star rating in the Consumer Focus best-performance table with British Gas in second position with four stars and Scottish Power third with three stars.

The energy companies have been under the cosh since they introduced significant gas and electricity price rises of up to 19%. The Guardian revealed that new analysis appeared to show sustained profiteering with a major, and growing, gap between retail prices and the wholesale costs they incurred producing or buying the energy.

The companies deny this but they are also facing a political backlash over the number of families being sucked into fuel poverty: one in four across England and Wales.

Meanwhile, there has been outrage at revelations over senior executive pay, with Phil Bentley, head of British Gas, earning a basic salary of £1.3m last year, enhanced by the exercise of share options worth a further £2.7m.

Vincent de Rivaz, chief executive of EDF Energy, admitted in September that trust had been lost: "We recognise there remains a widespread lack of understanding and suspicion of the industry as a whole, among the public, customers in general, politicians, regulators and others."