Hello @Andrzej Formela.
Sorry to hear about the bill increase.
Have you viewed the PDF bill that we produce in the app? This should explain any out of plan charges or what this bill refers to.
We recently also sent out notifications about a price increase due to RPI/CP increase for 2023.
If it’s a recurring increase then this will be the reason.
If it’s a one-off then it’s likely just an increase due to out of plan usage, change of plan, upgrade or change in payment date as these all incur pro-rata line rental.
Info on RPI here: https://idmobile.co.uk/rpi
Info on CPI here: https://idmobile.co.uk/cpi
Mohammed