Vodacom false advertising

Vodacom worse service ever - I am due for my upgrade I go onto my app to upgrade found a deal that suited me I select the deal go through the steps and it says at the end an agent from vodacom will come back to me. I don’t hear from vodacom so I do my upgrade again via the app select the same deal and afterwards I decide to call vodacom to check it. They inform me that it’s their mistake on the app and that it’s the wrong advertising and that the contract is almost double the price. Now for the last 5days they have been advertising this deal and I even went to a vodacom store so show them the deal and they recommended that I rather do the deal online. Now vodacom is refusing to do this as they say it’s a mistake. I’m sorry but this is false advertising and against the consumer act. I have the screen shots of the advertised deal and my whole processing of the upgrade via the app. This is unacceptable