MTN SUCKS

I was informed by MTN call Centre and MTN store Tongaat that my Black Friday contract could be upgraded by 31/12/18 .Went to Tongaat MTN store in mid Dec2018 and was told I have until 31/12/18 to upgrade and that they were very busy.Told to come in Later in month.I went in on 27/12/18 to be told that the offer is finished.I confirmed with call Centre that it never expired until 31/12/18.I emailed CEO ,Public Relations and received ref nos on enquiries but no response from MTN.Your call Centre response was worse -go back to the store.The stores response -speak to the regional manager.He never responds.Disappointing we expect large companies to have principles and honor your word/policy.If you do not how can the consumer do so.Next Step ICASA.