VODACOM OVERCHARGED VAT - 15.68%

I receive my account this month and the billing amount differed from other months. To my surprize I noticed that I had been charged 15.68% VAT !!!!! Since when has the VAT been increased? This cannot be 'just a mistake' as the computers should be programmed for 15% VAT. It might only be a small amount on my account but multiply that by a few thousand/million (customers) ??? Lots of money in Vodacom's pocket!! So please guys.... check your September 2018 accounts (and all future ones). If I was overcharged with 15.68% VAT so were you ALL MAYBE!! I reported this... still waiting for someone to come back to me.