I think a good place to start would be the consumption department at E.ON, is it them that will be calling you?

They will be able to go through the usage and your appliances and see where the energy is being used, they can also advise on tariffs.

You may also be able to talk about having a payment arrangement that will cover a longer period of time, this will bring the monthly payments down a bit for you.

I'm sorry that you are having so many problems.

As Jalexa says, it is good that you have your start readings, this means your accurate usage can be calculated whilst you have lived in the property.

Helena.