I've been getting estimated bills for well over a year now, despite having a supposed smart meter and my phoning monthly to leave a reading. I'm now a thousand pounds in credit and no on can tell me what my bill should be, yet they keep putting the DD up! I've been in so much contact with them to try and resolve this that it is past a joke now. I've had to go to the Ombudsman and ask them to help. Absolute clowns!!