Packet Switched Data Calls Charges!!!

I have an MTN contract on a MTN 200 package and my account is always between R650 - R1000 (over the years i have had my contract with MTN) rarely go over that. I get 150 MB of data. In the past if I went over my 150 MB I would get a warning to let me know my data was low and would have to purchase an additional data bundle. No problem. I was send a email with to download my April statement but can not gives me a error message, i see now on my May account that i was charged:<br> APRIL R 1970.83<br> MAY R 3027.85 <br> MY TOTAL OUTSTANDING IS AS FROM TODAY IT R4998.68<br> I have a cut of of R 1500 HOW IS IT POSSIBLE I AM BEING BILLED FOR SO MUCH. I CAN NOT AFFORD THIS!! Should my account have not been cut off?? why was it not!<br> Today, I get my statement and I see that I have been charged for \Packet Switched Data Calls". I have been trying to call customer care for the past two days....can not get through. Why has my account suddenly gone from capped to uncapped. To say that I am fed up with MTN is a massive understatement. My contract is up for an upgrade this year. I will definitely not be taking it. I will close my account at MTN. I do not want a generic apology! I want this resolved immediately!"""