Why does my meter reading not process automatically. I have to go on to my account and update before it calculates a monthly bill. I tried to change tariffs as asked and it wanted to charge me more per month for a cheaper tariff.
The default billing cycle is, I think, 3 months. Only if you want a PDF bill more frequently than that do you need to manually click the "enter readings" button.
Regarding the new tariff, perhaps you are paying too little per month and building up a debt? If so your monthly payment will likely increase to cover this, despite the standing charge and unit rate of your new tariff being notionally cheaper. Remember, even if a tariff is "cheaper" you'll still pay more if you use more, or if you haven't been paying enough previously.