My electricity provider EDF have just sent me a statement, and they're going to increase my monthly direct debit charge from £60 to £110. This is because they think I've used ~£600 worth of electricity in the past 6 months. Since I live alone and am usually at work, I don't think this can possibly be true. But how do I prove it to the electricity company? My meter agrees with their latest reading (I can't speak for the previous ones), and it does stop turning when I unplug everything. Is there anything else I can check, or do to contest this bill? Their lines are closed at the moment, so I won't be able to ring them until tomorrow.