Airtime and data complains

I have been having challenges with MTN airtime disappearance and data consumption. Im using Iphone 6 and its very easy to switch Off unwanted services on it. Recently i bought airtime and after that i bought data, to my surprise later when i switched ON data, my Airtime was gone....almost finished while i still have data on my cell.<br> <br> I called MTN to lay complain and the lady who was assisting couldnt deliver and i opted to speak to the Supervisor. To my surprise looks like she also dont understand. Apparently if you have data on your phone MTN can still bill you your airtime if you are running multiple programs. <br> This has been happening for some time and i fail to understand why would mtn bill me airtime even thought i have data on my phone??<br> I have majored in telecommunications and had worked for top companies but what mtn is doing is robbing us day light....and this thing that MTN bills a lot cause its using LTE is such a ****!!! whether using LTE or 3G or EDGE 10MB file is 10MB, why would you charge me 20MB file if im using LTE?i mean at the end of the day i only downloaded 10MB file,NXAAAA....such **** needs to be reported to ICASA and competation Commision