data usage

[sweetreese]

Is data taken from your plan if you are using Wi-Fi?

[commonsense101]

not if you are truely on wifi.. make sure you turn your data connection off. Your phone will always connect to the strongest connection, so you could have wifi on but the phone could still be accessing the mobile data network

[Hains1976]

How do you turn your data connection off and use only your wifi??

[tikibar1]

see if this works:

settings > general > cellular