Con Edision is back-charging me from over 2 years on heating gas charges the did notice until 2/26/09.

situation: In 7/06, My Lanlord changed the connection for my heat so that she would not incur the gas charge. Since then my gas charg increasd from $15 to $50. On 2/28, i received a letter from Con Ed stating that after careful review of my acct, my balance has been adjusted. When I went online to check the status of my acct, It read that I owe $918. When Icalled Con Edison to Discuss the matter, the Supervisor, Mr. Soto, stated that I should have noticed that they [ Con Ed] was charging me for cooking gas instead of heating gas. How would I kow that? There's nothing listed on the statement that states the difference. Also, I have let their Techs in to check the meter and not once was this pointed out. I have submitted complaints to the Public Service Commision and Better Business Bureau-I await their reponse. Obviously, the account Manager was not on his/her job and therfore they want me to pay for this. I will fight this if not resolved until the day I die. This is ridiculous!