Data from the Citizens Advice Bureau shows that most complaints received about SSE energy firms relate to two of the smaller, “challenger” brands – Extra Energy and Co-Operative Energy . The two firms received the highest number of complaints relative to their customer base size in the last three months of 2015 , in part because their rapid growth outpaced their customer care resources. “This latest league table tells two different stories - some suppliers have again proven they’re effective at dealing with customer complaints while others lag far behind. The only big six firms to appear in the bottom ten of the league table, behind Extra Energy and SSE , were Co-operative Energy and Npower , which have both faced billing issues caused by IT system upgrades. EDF Energy , which laid claim to the lowest complaint rate in the industry since the table was first published the last three months of 2015 , was narrowly beaten to the top position by EDF Energy .
Data from the Citizens Advice Bureau shows that most complaints received about SSE energy firms relate to two of the smaller, “challenger” brands – Extra Energy and Co-Operative Energy . The two firms received the highest number of complaints relative to their customer base size in the last three months of 2015 , in part because their rapid growth outpaced their customer care resources. The only big six firms to appear in the bottom ten of the league table, behind Extra Energy and SSE , were Co-operative Energy and Npower , which have both faced billing issues caused by IT system upgrades. EDF Energy , which laid claim to the lowest complaint rate in the industry since the table was first published the last three months of 2015 , was narrowly beaten to the top position by EDF Energy .