MTN the worst one of them all.

I recently upgraded my contract my with MTN, and the agreement was that I will not pay the first three as advertised on their online store and pamphlet. But to my suprise it reflects the amount of R691. I have sent about 4 e-mail asking for this to be corrected and to this day it hasn't been resolved. I'm very disappointed with the service that I am getting from MTN after so many years with them.