RIDICULOUS BILLING

MTN advised that I had no limit on my cell phone account, which was verified untrue when I checked my account, on their document it clearly states that I have a limit of R900.00 - I have been billed a ridiculous amout of over R2 000 and prior to the previous month an amount of R1 400 +/- how is this possible when I have a limit. I am in possession of a print verifying this.Furthermore, I called in to cancel my contract last week, on a recorded line with MTN. they have renewed my contract for the MONTH despite me cancelling my contract. I am highly frustrated that I am now going to be charged against my WILL. I Keep calling their call centre as WANT THIS FIXED ASAP but everytime I get a call centre person keeping me on the phone and promising me to rectify with nothing being done!!!!! And I have requested that A PERSON CONTACT ME REGARDING MY LIMIT AND WHY I HAVE BEEN OVERBILLED DESPITE MY LIMIT!!! AS WELL AS MY CANCELLATION but NOBODY has any decency to contact me (a customer of well over a decade with MTN ) This is the thanks I get for my Loyalty with an undeserving company like MTN. I need a resolution to my problems and I need this finalized as it is causing undue stress.