Missing data

I'm really upset, for I am loosing data so fast and phoned Vodacom regarding the data that is going so fast and asked them how is it possible to loose 2G in one day. I requested for a print out to see where the data has gone to, almost one week ago and still nothing. If this is Vodacom that is just so expensive in data, this is the last time I am a Vodacom customer, because never heard of MTN customers complaining of their data going to fast or so expensive. I am already done with 4G this month which never happened before, and then I am even on WIFI during the day at times. really I want to know how this is possible. Frustrated.