While I have a technical background, I only just recently purchased my first smartphone, and I'm stumped regarding an explanation that my carrier is giving me.
I installed an app from them on my phone that tracks the amount of data usage and balance. Last time I checked, the usage was sitting at around 490 MB. I turned off the device completely and left it like that for about 2-3 days, as I did not need to use it during that period.
I turned it on today again, and it shows that 540 MB have been used. I called the carrier, and they explained that this is because of mobile data being turned on in my phone's settings. They claim that the phone will continue using data even if it's turned off, as long as this setting remains on.
Is this a sensible explanation?