Data disappearing - Telkom

I had 850MB on mymobile device this morning. I decided to purchase another 2Gig around 10:00am because I need to work. Usually I use about 700MB a day when I work using hotspot. Today, within 2 hours, the 850MB depleted and 267MB of the 2Gig remained. All that data within 1.5 hours. I called telkom & the consultant wanted to tell me what I used & not what the problem was. No background apps besides whatsapp & facebook, no apps were downloading because my phone not connected to the wifi. Very poor service & to think I ported from MTN to Telkom because of the bad service.