False Advertising

The latest April 2016 MTN promotional pamphlet advertises that you can take out a 24 months contract on the Samsung S7 or S7 Edge and with this you will receive a 64GB SD card for free. On Friday the 1st of April I went to the MTN store in Karaglen (Edenvale) and signed up for the deal. They unfortunately didn't have the SD Cards in stock and told me that they would phone me when it arrived. On Tuesday the 5th of April I was informed by Daniel at the store that there had been an issue with the SD Card stock and they could no longer offer the 64GB SD Card, however the could give me a 32GB SD Card instead. Don't get me wrong, the service offered by Brenda and Daniel in the MTN Karaglen store was fantastic, however why is MTN advertising and promoting that the Samsung S7 comes with a 64GB SD Card if these are in fact not available? I have now had to accept the 32GB SD Card however I feel that the terms and conditions of the contract that was offered to me have not been met. I've been with MTN for over 10 years and have 4 devices on contract with you. Surely you should consider offering your customers something that you can in fact deliver on? I want answers...