Vodacom could be selling us data at an exorbitant price and then still not delivering the full amount??

I recently converted my personal contract to a business one, and then moved to a small holding, that has no fibre or Rain as alternative options. This is important back ground having been a happy customer with Vodacom for a long time and received data previously from Rain or fibre. I was given limited home data options and had to go with a 100Gb modem linked to a tower. Since we had to work from home so much I sped through my data quickly so had to buy extra bundles. Again, given very limited data bundle options from Vodacom. The most data I could buy for 7 days was 5GB...really.. anyway, since last year I have been buying these 5GB bundles to get through the month. However, in every instance when I chose that 5GB option and paid the required ,exorbitant R199, they only delivered 4GB??? So I would phone and then( to get hold of a business consultant was traumatic) and then in each case they questioned me, assuming I had made a mistake. So after a time they would come around and realise the problem was theirs. The 1GB was then delivered, saying they would speak to technical and give me feedback. Naturally that never happened. Last night again, bought 5GB for 7 days, they delivered 4GB. While this is unacceptable I am wondering how many other people buy data and check what is delivered...Vodacom could be ******** us in huge numbers...Sadly, I can't bin them as I have a 2 year contract and no other data options.