EDF Energy has been ordered to pay £3 million by Ofgem for breaching complaint handling rules.

It follows an investigation by the regulator after complaints about the Big Six supplier soared by 30% when it introduced a new IT system in 2011.

Ofgem said the power provider did not have appropriate procedures in place to properly receive, record and process all customers’ complaints between May 2011 and January 2012.

The £3 million package will be donated to not-for-profit initiatives that provide free advice to vulnerable customers regarding debt and energy.

Sarah Harrison, Ofgem’s Senior Partner with responsibility for enforcement said: “EDF Energy failed to have sufficiently robust processes in place when they introduced a new IT system and this led to the unacceptable handling of complaints.

“It’s now vital for EDF Energy and the industry as a whole to truly put customers first and put adequate resources in place to deal with complaints.”

EDF Energy said it has “taken this matter very seriously” and “co-operated fully” with Ofgem.

Managing Director of Customers Beatrice Bigois added: “Despite our best efforts and extensive planning to manage this transition in 2011 without impacting our customers, we recognise that for a period of time the service to our customers was not up to the standards they deserve. We apologise to those customers who were impacted during this period.”

All six of the Big Six suppliers have now had to make similar payments within the last two years.