Empty promise of the MTN 12 month free (2GB monthly) data

On the 23rd of November 2018, I upgraded my cellphone contract with MTN at their Centurion Branch. As part of the new contract package / deal, I was promised that I am going to receive monthly 4GB data (which consist of the 2GB data that I am going to receive for 24 months and an additional free 2GB data for 12 months). Up to this date, I haven't received the 2GB free data as promised and as indicated on the signed contract. I went to the branch to inquire regarding the "promised free data" on numerous occasions but still today, I haven't received the free 2GB data. It is almost six months now since the contract has started but I havent received the free data. The consultant who assisted me at the branch (Ms Doris Malata) told me that she referred the matter to the Head Office, but still no response from them. It is frustrating because it seems as if, MTN has made an empty promise to me in order to secure a 24 month cellphone contract with me.