I have a pay and go plan in which I get free texts and Internet for 1 month every time I top-up. When this expires I stop using my internet. However, I still receive a daily message saying that I have used £1 worth of data. Why is this?
Because something on your phone will be working in the background. Push services? Updates?
Would need to know your phone and what sort of apps you use.
Turning cell data off should help.
If it auto updates that could be it.
Just turn Cell Data off when you don't want it, saves going through all your apps.