Disappearing data

Whatapp used over 350mb from 20th to 22nd March 2016. I tried to call 808 but they were unable to help. My husband is with Telkom Mobile (which ***gybacks on MTN) and his whatsapp is still using heaps of data (401 mb since about 20th March). He has tried to change settings so that whatsapp only receives messages when he goes into it, but the huge data usage is still happening.<br> <br> We are disdusted by this, especially since when I called MTN they were unable to assist. This is a huge problem, as it is guzzling all my husband's data.<br> <br> I would like to know why this happened and is happening, and whether we are going to be reimbursed for all the data we have lost.