Data Loss and *********** Customer care agent

I'm rapidly losing data from my mobile device whilst it's connected to my home WIFI(Fibre) which is uncapped. logically the mobile is not supposed to be consuming any data from my Sim card, as the mobile device is connected to WIFI. I called the Customer Care for assistance, and I was introduced to the most *********** and rude CSR. She kept reassuring me that there is nothing she can do to help me, even prior to listening to my complaint/query. She defied a logical conversation and resorted to undermining my intellect, matched with an attitude Her name is Sthembile Msomi