Bleeding data

Hi I've been a Vodacom user for a while now. Apart from slightly higher costs I always appreciated generally good service as well as decent network coverage. I have a contract with Vodacom where monthly I get R350 airtime. I use this to buy 3GB data for R299 on the first of every month. I accept that on some months my data usage may be higher than others and that I will run out of data before the end of the month (I don't usually worry about this as I have WiFi at home). This last week such an occassion occured where I ran out of my 3GB monthly data. I then bought a week bundle for 250MB. Everything was going fine during the week and I was maybe using around 30-40MB per day so I was working under the assumption that this would be fine. On Friday however (when I had around 160MB - I know this since Vodacom sent me a message saying this is how much I had left), that data just vanished within the space of 5 minutes. I got successive messages stating that I was running out of data until I got the inevitable "you have used up your data bundle message" 5 minutes after the "you have 160MB left" message. There is no way that I could have used up that much data that fast. But I was willing to give that up as a random chance. I took a look at my data settings and how much data the various apps were using (which has never been a problem before for me) and minimised the usage where I could. Then I bought a R17 100MB bundle for the week. That expired in THE SAME DAY. Within a couple of minutes. Now that is NOT possible. Throughout the weekend I bought numerous data bundles from Vodacom (often the 100MB ones for a day). They literally just vanished. I know my data usage, and it isn't that much. I can barely now use GPS to navigate somewhere. I rarely (if ever) watch videos when I don't have access to WiFi, and when I browse the internet it's to websites that generally should not use up much of the data.

Now I accept that maybe it is my usage, although why it is only an issue now (1 and a half years into my contract) I don't know.

Yesterday I asked for a call back from a consultant to assist with the issue and I have not got one yet, hence I am writing this up.

As I am doing this I know I am bleeding data without any explanation as to where it is going.