UNHAPPY OVER BILLED CUSTOMER

I Upgraded my Contract with MTN which was supposed to be R579 per month. To my surprise at the end of the Month (March 2018) i was debited R779. I contacted them on the 4th of April querying my billing. My billing is still not resolved even today (2 May 2018). Everytime i phone i am being sent from pillar to post. Again i was debited R779 at the end of April. Everytime i phone i have to narrate the story over and over. Some of the agents are just clueless. they dont seem to know their job.