EDF have overcharged me by approx. £2,000 over the past 18 months. They then pushed me to making a Complaint to the Ombudsman Service who have upheld EDF's actions as Condition 3.5 of EDF's Terms & Conditions state; "Where we are entitled to change the conditions of your contract, this includes the right for us to change your product or the way you pay and how often you pay." Be very careful of the small print in the EDF Terms & Conditions as the Ombudsman will not find against them due to this clause. EDF are obviously very experienced at "gaming" the Ombudsman Investigators.