shaunc1987:
You are right about the 7 days notice of disconnection. Whether they can prove hand delivery of the notice is perhaps a matter of fact you will be able to challenge but it hardly helps in the short term.
The CAB online info is here...
http://www.adviceguide.org.uk/index/your_world/gas_and_electricity/electricity_supply.htm#Arrears_and_avoiding_disconnection
Go through it with a fine tooth comb, in particular there is a Consumer Direct number to call.
Now this not meant to be judgemental but rather to help you focus on other issues. According to the advice guide, action should not begin until 28 days after a bill. Did you receive a bill and what did you do on receipt of last bill? Were there arrears on the bill before that and did you discuss that with edf? Disconnection is unusual while there is ongoing customer discussion about arrears recovery.
Unfortunately your post appears silent on that issue which is not helpful.