Not happy

I'm not happy with the billing of my month to month sim card.

My payment date is the 15th of every month. I received my package on 08/05/2023 and only started using it the following day.

So the billing cycle requires me to further pay more even though I used it for a couple of days.

I'm not happy with the billing of this account. I was told by the sales consultant that I will only pay the following month.

I would like to cancel my subscription and pay for the data I have used