Why am I using up data on my Apple IPhone 6s when I am at home and have wi-fi. Is my phone set-up incorrectly. I bought phone on a Monday and during this time was learning how phone works and by Thursday I am being told I am almost out and need purchase more. I only have the 2GB since we don't use our phones that much used up that much data while at home all week for vacation. What am I doing wrong?