I think my problem doesn't really have a solution but I would like to share and hear your opinion on this.
I moved into my one bed flat in July 2012. At that time, my landlady said she has lost keys to the elec cupboard and would get me one asap. However , we got it after three months later ( more due to my fault of not chasing up often). The supplier was EDF and we probably were left with the highest paying tariff after the previous tenanct moved. I changed my supplier in December
The end result was paying about £380 for 4.5 months for a one bad flat (£84 per month roughly). From then on, I was with Ovo and EDF Energy blue tariff which amounted to roughly 50 per month.
Few weeks back, I got a letter from EDF that I have still got £178 left to pay them (on top of the £380) from my older account and that they will refer me to debt collection agency. I have ordered the statements and am yet to see the details but even without them £125 per month from end of July to beginning of December seems too steep for 1 bed flat. Even if I had blasted my heating in October and November, I doubt it could have gone that high?
I don't suppose I can seek help from energy ombudsman that I feel I am unfairly being charged - got no proof! And probably my fault for not cottoning to it early and making sure to get a better tariff.