My data dissipears within 5mins

I spent almost R200 in less than 5 hours on data and it just depleted within seconds after purchased! and my phone shows i used 112mb in total on all my apps. Where does my data go? Dayligt *******! I want an explanation on my data depletion. Had to turn my phone off cant receive anything unless im on wofi cause it just eats my data. I only sent 3 whatsapps and 50mb was depleted. I have screen grabs and account proof about the amount of times ive had to buy datat in less than 5 hours, my backround app refresh is off and phone was lying in ky bag and datat flew without me even using my phone. Absolutely ridiculous