Energy supplier npower has written to millions of customers to apologise after what was described by Ofgem as a "serious deterioration" in customer service. His chief executive said he will be receiving a "much reduced" bonus because of the failings.
Energy companies were guilty of "outrageous blackmail", according to a consumer campaigner, who saw the latest attempt to cut bills by £50 as an empty gesture.
"I'd be more impressed if energy companies had said they were going to lower bills by an average of £50 and were going to do it now," Ann Robinson of Uswitch told Daybreak.
She expressed scepticism over the "Big Six" energy companies motivation and what the Government could do to intervene on behalf of struggling consumers:
"I think there is a limit to what can be done. It is playing around the edges. It is not real. I also hear for example, is that one of things that the energy company is looking to is to delay even more the smart meter programme."
Many npower customers will have noticed a serious deterioration in service levels over the last year.
The huge growth in complaints about npower is wholly unacceptable and is an issue that Ofgem takes very seriously and is why we intervened in this case.
npower's commitment that its customers will not lose out financially as a direct result of the company's billing system problems is important and we will expect npower to do all it can to identify and rectify such cases.
npower's chief executive has apologised "unreservedly" after billing errors affected thousands of customers.
Paul Massara wrote in a letter to npower's 3.4 million customers: "We've let many of you down recently in the overall levels of customer service we've been providing. We apologise unreservedly."
He said the billing problems arose after customer details were transferred on to a new computer system. Around 700,000 customers are thought to have been affected by the problems, though it is believed the vast majority are not financially worse off.
Mr Massara said the issue was being dealt with as "our top priority", and hundreds of staff were working to address it.
Many customers affected had already been contacted individually to address specific problems and others would be, he added.
Gas and electricity supplier npower has written to its 3.4 million domestic customers and donated £1 million to vulnerable consumers after billing errors led to it being the most complained-about energy company.