Extra Energy received the highest number of customer complaints on record between January and March this year, according to Citizen Advice’s data.
For every 100,000 customers, it received 1,916 complaints in the first quarter of the year, the highest number recorded by the charity since the data was first compiled six years ago.
It received a score of 2.05 stars overall, out of a possible five, based on a number of factors including customer service and complaints handling.
Record-high complaints: Extra Energy receives 1,916 complaints for every 100,000 customers
It also scored badly for customer billing and ease of contact and received two out of five stars for both.
One area where it did well was for switching customers where it received a top score of five out of five because it successfully switched 99 per cent of customers within 21 days.
Citizens Advice said it had seen examples of customers not being able to speak to the energy provider and cases where they were charged twice for the same bill.
Back-billing was also an issue and one customer it spoke to had received a bill for £4,500 after the company failed to collect payment for 18 months.
Extra Energy was followed by Spark Energy, Co-operate Energy and Green Star Energy at the bottom of the table with scores of 2.3, 2.6 and 2.85 respectively.
Scottish Power made the biggest improvement, with 3.15 stars, an increase from 2.75 last March.
At the other end of the scale, small energy firms dominated the top half of the table and Ecotricity was in the top spot with an overall rating of 4.4 following by E (Gas and Electricity) and Flow Energy, with scores of 4.1 and 3.9 respectively.
EDF Energy was the highest-scoring big six energy firm, with a score of 3.75, followed by SSE and then British Gas.
Energy suppliers are given an overall score out of five in the charity’s quarterly table which looks at: customer complaints, successful switching numbers, customer service, how easy bills are to understand and whether the supplier is signed up to the switch guarantee, committing them to switching a customer within 21 days.
Gillian Guy, chief executive of Citizens Advice, said: ‘Customers should know what they’re paying for when choosing an energy supplier.
‘How easy it is to contact your supplier, how clear your bill is and how easy it is to switch are all important factors when choosing an energy supplier.
Top players: Small players dominate the top of the table with Ecotricity in the top spot
‘We have found that some energy suppliers have made improvements in the service they provide, but it is disappointing that others appear to be getting worse.
‘It’s important that all energy companies are constantly trying to improve, to make sure they deliver the best service they can to consumers. This must include sending out accurate timely bills, having the right number of staff to answer phone calls quickly, and having the right processes to deal with complaints quickly and effectively.’
Ben Jones, managing director of operations for, Extra Energy, said: ‘We’ve always been honest and transparent about the growing pains we experienced, which occurred during a period which saw our customer numbers expand rapidly due to the market leading tariffs we were offering.
‘But we’ve also always been clear that we are making unprecedented investments to overcome these issues for good.
‘We won’t accept a short-term fix, and making major changes to our business to address such challenges takes time. We have a plan in place and we’re seeing significant improvements, particularly around switching.
‘We want to make the market work better for consumers, and we’re continuing to work incredibly hard to ensure we can deliver excellent service for our customers as well as competitive tariffs.’
The firm, which is currently being investigated by the regulator Ofgem for customer service and billing procedures, also told us it had invested heavily to overcome the historic issues it has faced including expanding its operations, employing hundreds of new employees and last year moving to new premises.
The data from Citizens Advice is compiled by looking at a number of sources including, Ofgem, the Energy Help Unit, the Energy Ombudsman and Energy UK.
THE FULL COMPLAINTS LEAGUE FROM JANUARY TO MARCH 2017
Provider Star rating Ecotricity 4.4 E (Gas and Electricity) 4.1 Flow Energy 3.9 Economy Energy 3.85 EDF Energy 3.75 SSE 3.75 British Gas 3.7 Utilita 3.4 Utility Warehouse 3.4 Eon 3.15 Scottish Power 3.15 Ovo Energy 3.1 Npower 3 First Utility 2.9 Green Star Energy 2.85 Co-operative Energy 2.6 Spark Energy 2.3 Extra Energy 2.05 Source: Citizens Advice, 22/06/17