Contract advertised not honoured

I received an sms from Cell C stating that my contract was due for an upgrade and that I should view their deals on their website. I did and came across a deal that I was interested. I then sent a request for both of my contracts to be upgraded to the one that I viewed on the Cell C website. It was the Epic200TopUp package with a Samsung S6. I also called into the \Retentions Call Centre"and Tsidi advised me to send a screenshot of the deal"