Data goes bye-bye

All i need to know if why does my data fly so quickly, I did some test over a few months with my wife who is with Cell C. first test: we both buy data the same day at the same time (1gb) we both enable the same social media platforms and more or less surf the same channels. My data last about 15days and hers carries over 30days to the new month. <br> second test: Same as above but i switch off most of my social media platforms and dont use google on my phone, my data last just over 15days and hers is obviously the same. Are you guys robbing us who are contract customers!!!! I need to know *** is going on as my contract ends in July and i am thinking about leaving vodacom after many years of being a customer.