New energy firm Extra Energy tops complaints list
A small energy firm has seen a record proportion of customer complaints for any supplier over a three-month period, figures from Citizens Advice show.
Extra Energy, which launched in 2014, attracted 1,682 complaints per 100,000 customers between January and March.
This is the highest ratio of complaints over the five years the data has been collected.
The company described the start of the year as "challenging" and has apologised to customers.
Extra Energy has more than 500,000 customers after consistently offering some of the cheapest tariffs in the market since its launch, but said it had struggled to cope with demand.
"It is true to say that the first quarter of the year was a challenging period and some customers were affected. We apologise unreservedly to every single customer who has experienced problems," said Ben Jones, managing director of operations at Extra Energy.
"Unfortunately we did not put customer service resources in place quickly enough. Thankfully these problems are largely a thing of the past."
Citizens Advice chief executive Gillian Guy said: "Energy consumers continue to face a gamble when it comes to good customer service.
"The latest league table results show both small and large suppliers delivering a good service, proving that a company's size is no excuse for poor performance.
"It should be every consumer's right to receive a high quality service from their supplier and standards must be improved across the board."
SSE was the best performer in terms of how effectively customer complaints were dealt with by energy companies, according to the Citizens Advice table.