Some of the UK's biggest energy companies have been ranked as being the worst for customer satisfaction in a nationwide survey.
The Which? poll, coming as a spate of energy price rises hit consumers, put smaller firms at the top of the table for value for money and customer service. The big six, which dominate the market with a 98% share, all ended up at the lower end of the scale.
Energy giant npower received the lowest overall score in the survey of more than 10,000 people, with a 39% customer satisfaction rating. It was the second year at the bottom of the results table for the company. EDF Energy had the second lowest rating of 46%.
The chief executive of npower, Paul Massara, said he was "disappointed" by the results and apologised to any customers feeling let down.
Good Energy, which supplies electricity from renewable sources, was top for the second year running with 85% customer satisfaction and was also voted as the best energy supplier.
Customers praised it for publishing a regular newsletter containing tips on saving energy and the fact that prices had been held for four years until October 2012.
Its founder and chief executive Juliet Davenport said: "This result is proof that if suppliers choose to invest in high quality customer care, through things like Energy Saving Trust accredited advice and internal training, then they can really help customers save money on their bills."
A total of 17 energy firms were rated for the Which? report, with the results showing opinions on clarity and accuracy of bills, complaints handling, helping customers save money, customer service and value for money.
Only two of the six major energy suppliers, E.ON and SSE, made it into the top 10, in joint ninth. British Gas and Scottish Power, the remaining members of the big six, were joint 11th place.
Which? executive director Richard Lloyd said: "Yet again, customers have told us they are fed up with the way the biggest energy companies treat them, but the complexity of energy tariffs makes it hard to shop around."