MTN Contract centra not willing to fix their mistake

I recently upgraded my contract on the 25th of November. the upgrade was done via telephone the deal was available as part of Black Friday special. Somehow the deal was not processed by MTN employee Bandile. Now I'm being told that the deal is not available and they cannot help via their contract upgrade centre.

This kind of service is not acceptable when an employee makes a mistake and the customer has to suffer the consequence.

Regards Sipho Msibi