I've turned off my data and wifi, why are both usages going up?

[Windows Central Question]

o2 customer in the UK. I don't use the internet on my phone, so manually turned off data and wifi, but usage is still going up. How is this possible? Is it an apn? Can things run in the background even though data and wifi are turned off?

 

[Kieran Jeffery]

How much is it going up by? Also, could be picture messages if you send those.