Suspiciously high consumption and bill charge

What rating is the heater? How many hours do you have it on for?

If it is the only heater that you have then let’s say that its a 2kW Esoso ceramic heater.
To use 1000 kWh per month on it’s own you would need to be running it on full power for 16 hours a day. (2 x 16 x 30 = 960).

The thing that stands out is that you say:

I dont have anything else that notably consumes energy

However you may be surprised just what things consume, so just what else are you using?

Presumably you have an electric shower? Electric showers use a lot of power.
Maybe a heated towel rail in the bathroom?

How are you heating your hot water?

How are you washing your clothes, bedding, etc?
How are you drying them? Tunble dryers use a lot of power.

What are you cooking on/with, electric hob/oveh, microwave, Air fryer, something else?

Do you have a dishwasher?

Hey ​@kalllll 

Sorry to hear about this, though I’m glad to see one of our community members has already stopped by with some really helpful questions. 

It would be really good to know some more information so we can all advise as best as possible.

I also wondered about the bills themselves, are these based on the smart meter readings? Or are they based on estimates? I know you mentioned the smart meter is sending readings, do you know how often these are being sent? Monthly readings can lead to estimated bills, if we’re unable to use more accurate half-hourly data.

If you’d be able to give us some more information based on the above questions from myself and Nukecad, we’ll also hopefully have a better understanding of what’s going on.

The following topics may also be helpful here in the meantime:

Hi ​@kalllll 

Could you post some screenshots of what you see on this page on a typical day

https://account.ovoenergy.com/usage?datePeriod=daily&unit=kwh

Then we can see how much electricity you are using every 30 minutes on a typical day

It will give us some idea of when the usage occurs and hence what is happening