Unexplained data Loss

I have two MTN contacts and over the past month I have been loosing data at an astronomical rate with no explanation. 1 GB (Plus addition 1 GB supposedly free) of data doesn't even last me one week. I checked my iPhone handset and switched off all \Background App Refresh"hoping it would assist and I still loose data at the same rate.<br> <br> This morning I purchased R30-00 at 09:01 airtime and converted to 200MB daily bundles and within 30 minutes my data and airtime was depleted. I repeated the exercise of buying data at 12:57 and again within 30 minutes my data and airtime was depleted. I called the 1555 call centre and was told that it was not yet updated on their system and maybe the following day it would reflect. There is no reasonable exlplanation forthcoming from MTN and I believe this is ****************"