*****ing Data

I regularly buy 3GB of data for seven days which lasts me at LEAST five days. Today, I buy 3gb of data, and after ten minutes of using Waze and sending a single Whatsapp, I am down 1.7gb of data in fifteen minutes. For the next fifteen minutes, I am no longer using Waze and sent a few messages, data completely ran out! Obviously my data was ******. I went to the Vodacom store and he said I had to call Vodacom because he can't check data usage (quite suspicious. When I called Vodacom, I could only speak to a robot who could not assist me. I bought another 3gb package and three Whatsapp messages used 600mb of data. My phone used an additional 200mb of data in the office ON WIFI within minutes. What am I supposed to do? Spend R1000 on data this weekend? No customer care WHATSOEVER.