EDF has received a record number of complaints with one in eight of EDF's 5.5 million British customers calling EDF to complain about its poor service.
In the 12 months from October 2010, complaints soared 35% from 514,678 to 707,783.
EDF is now Britain's most complained about energy supplier.
EDF also faces the prospect of multi-million pound fines over its handling of customer complaints following an in depth Ofgem investigation.
An Ofgem spokesperson said "breaches of the complaints procedure were taken very seriously". British Gas being fined £2.5 million and npower £2 million.
On 10 November 2011, EDF was fined £1.28million and two of their senior directors were jailed for their part in hiring a computer hacker to spy on Greenpeace to protect the company's French nuclear programme.
