My data just dissapeared

Okay so, here is a little background to my complaint. I currently have Wifi both at work and at Home. So i buy really limited amount of data at any given time. However over the last two days i have spent more money on data than i would in 3 or so weeks. <br> Yesterday just after 6pm, i bought 100mb of data, knowing that i would need it for something specific and so i did one or two things with my phone and today at about 4pm i got a message saying that my data has been depleted.Later about 5:30 i bought 30MB of data which i thought would last me a few more days. Well i then sent 3 messages to a friend via whatsapp 1. No other apps were open and 2. My data was gone. Even before i used it. I then called vodacom and spoke to some white guy who hang up on me and then i called again and spoke to Nthabiseng from the data department and she told me to \Go to my phone manufacturer to find out what is wrong with my phone."I then spoke to her supervisor Thabiso who hang up on me. And what makes it worse if that this isn't the first smartphone i am using so saving data for me is as important as saving money and i don't have money to waste. I think its time to port. VODA Service SUCKS!"""