Ridiculous data charges

I loaded 150mg data this morning and made sure to restrict data services on my phone since I've had the same bad experience a while ago and was told other applications running behind ate my data.....guess what??? data gone in 7 minutes!!!!!!!!!! next thing I spoke to a consultant at MTN by the name of Thandiwe mncube who told me the system had not updated, told me to call in 30mns, when I called in after 30mins I was received by another consultant by the name of Geogina Masose who told me an application was open and ate my data...I told her I was on watssap for 7mins and her reply was that that's why my data depleted..i asked her how come I'm charged 150mg for 7mins on whatsap plus my remaining air time. She couldn't answer me. she left me hanging on the phone without attending to me. I then called in the third time and demanded to speak to manager and was told supervisors don't take calls by Mampho..she gave my details to a supervisor apparently by the name of Precious kwanana who promised to call me back and still hasn't. why are we being ****** why????