Ridiculous charges followed by no Feed Back!!

My mother recently received a bill from MTN for R13000 on a Prepaid account! the account was moved from contract to prepaid on the 20 april (confirmed by mtn) then the June bill was R13000 We have tried unsuccesfully via the call center and email for over a month and are receiving dead ends at every turn we don't know what to do anymore! they are going to try debit it again! We think due to Strike it was not cancelled and perhaps an employee has been running up the bill in the interim! Also the credit limit is R1900 how is this possible!!! I am absolutely fed up with the lack of support and customer service from MTN we have treid all the methods to contact and deal with this and are now being forced to take other actions, and should this matter not be addressed i will make it my mission to go public with this story in every way possible as I am sure this is no the first time this has happened!<br>