Unresolved contract dispute

I Upgraded my contract on Black Friday 2024 at the cresta MTN shopping mall. Upgrade was a yellow plan with an additional 9gb of data(which was part of the black friday deal). However, the sales person (Nontuthuko Khubeka) did not upgrade as she should and now I am NOT getting my 9gb data. I have gone to see Nonththuko at Cresta Mtn every month since December 2024 to get my contract resolved. Nothing has been done to resolve my dispute. I have also called the 135 number. Again I was transferred to 6 different people and NOT person took the INITIATIVE to help me!!!!! I am at my wits end.....MTN Customer Service is non existent!!!!