Incorrect Billing not resolved for 12 months!!

I had been incorrectly assigned to the Anytime 350 package when my contract is in fact for the Top Up 350 package. Because of this error I was billed R2500 for the month of August 2014 and when I enquired with MTN the then call centre agent refused to assist me over the phone and insisted they could not amend the mistake and informed me only the branch could assist. Eventually after numerous phone calls, I was assisted by call centre agent Paulina Dikgale. She logged the incorrect billing and stated that I would be issued with a credit note for the month of September 2014 - as I had again received a bill to the amount of R4000.00 as the incorrect package was still reflecting against my name. After numerous emails to Paulina Dikgale, who was either not responding or off sick, I have yet to receive the promised credit note. I have all interactions on email and as per all MTN call interactions, all phone calls were recorded where the agent stated that I was to be issued a credit note for the amount of R5514.40 (interest is collecting on the outstanding balance). My account was suspended in April 2015, due to the outstanding amount being too high. MTN *****!!!