MTN's data that seems to "disappear" on its own - even without having your computer switched on.

Trying to get anything sorted out with the MTN call centre is like having all your teeth pulled without any pain ****ers. AND you never win - there is always a system that protects MTN. I have a data contract of 20 GIG a month, with new data starting on the 21st of every month. On the 20th of March 2018 I spent the whole day at Joburg Gen oncology department with my mom - from 7 am till 4:30 pm and then traveled home for another 90 minutes. I did not switch on my laptop or used my data toggle. The 21st was a public holiday and again I did not even open my laptop and therefore did not put in my data toggle. On the 22nd March 2018 I opened my laptop at 9am and inserted my data toggle at 9.20. When an sms flashed onto the screen saying my bonus night data expired it intrigued me, and I went onto the MTN site that showed I have only been active for 11 minutes, but instead of 20 gig, I only had 13.23 GB. The next page showed that my monthly usage was "only" 5.12GB - which does not add up to the 6.77 GB missing and which I apparently used within 11 minutes - in a rural area with a download speed of 9KB a minute. Trying to query this and ask how this is possible, is like trying to ask for an explanation of why we do not have world peace? Seemingly beyond any system at MTN. All they can say is we need to refer this to the technical department, who says their system shows the data used, but they cannot give me the info, as I have not paid for a detailed bin - as part of my data only laptop monthly contract. This is not the first time. It seems MTN has a wonderful system where they give you the data you pay for at exorbitant prices, but then it "disappears" into thin air as quickly.