Breach of Contract---Vodacom

I have had a contract with Vodacom for some years and on expiry roughly two years ago I continued with a month to month subscription. On Monday this week I elected to renew my contract in order to get a new handset. The lady I spoke to at Vodacom agreed to the following:

Smart S+ Plan including 200 mins talk time, 200 SMS's and 650Mb Data and an iPhone 6 32Gb, for R429 per month. PLUS because I already had an extra 1GB of data on my current subscription she agreed to an EXTRA 2GB data. All of this was voice logged and I was informed that someone would confirm this and arrange delivery. After hearing nothing for the next 2 days I received a call yesterday from a separate person who tried to renege on the verbal contract and reduce my Data back to 650 Gb in total. This is absolutely disgusting behaviour on their part and not acceptable. I protested strongly and was informed the matter would be escalated...…….still no response from Vodacom!!!!!!!!!!!