Airtime just disappears

For the third time in less than a week my airtime disappears.

On Sunday evening I bought R35, was on Facebook a bit, sent a few messages then switched my cellular data off so that my airtime is not depleted! Guess what, woke up to find my R35 airtime GONE.

Bought another R35 after that and went to work where I am on STRONG wifi all day, get home, R35 GONE! I buy mini data bundles so that my airtime is not used up but it still gets used up! How is it possible that R70 airtime just vanished whilst my phone's data is OFF in less than 24 hours?!

Firstly I have NO automatic updates so please Vodacom if one of your consultants tell me that stront one more time I will lose it! I have NO background apps running! I have NOTHING that should be taking my data yet you feel it is your right to just deplete my airtime????

Then I get the stront that you are investigating but I hear NOTHING back about the investigation!

I want to know why Vodacom when data first became a reality your clients had to buy airtime and convert it to data yet now with so many technological advances it is impossible for you to differentiate between the two? Why is Vodacom not supplying two separate things here? This is HUGE problem yet Vodacom in all their "intelligence" can't find a solution? Please man! If you could do it in 2008 you can do it in 2017!