408.00 electricity bill

Hello can anyone offer some advice please. My friend has just received a combined gas and electricity bill from dodo for a one month period totalling 408.00 . She has a combined electricity and gas account with dodo . There are three people in total living in the house with an ordinary life and no large consumption of electricity. 408.00 seems very expensive for a one month period considering their usage is normal. I have requested dodo email her a copy of the last six months of bills and I will post the details here when they come through. Any other ideas appreciated thanks Grant