Stop *****ing my airtime

My airtime keeps disappearing EVERY DAY, I'm on WIFI 24/7 so you can say I use it for data. I hardly make any phone calls (you can check my call log) and when i do make calls, it doesn't last for long. I'm not subscribed to anything in fact I blocked all applications so where does my airtime go?? Please explain to me in writing why I lose my airtime DAILY!! This is very frustrating and totally unacceptable.