Unacceptable data “usage” on Vodacom Prepaid 4G

My data is being used at 3x the rate of actual usage on average on prepaid network.

I was watching the stream of 720p video for exactly 9 minutes and went from 783 MB “less than 70MB” without doing anything else, and no apps or data being used in the background.

The stream is variable between 5MB-6MB/s, which works out around 240MB / 10 minutes of viewing time. I lost 3x that and an explanation is required.

This is **************** and is unacceptable.