MTN over billing

To whom it may concern,<br> <br> In the last 3 month's my bill has increased significantly from its normal amount of about R550.00 from January 2015 to April 2015 to R595.84 in May 2015, R1678.00 in June 2015 and R775.24 in July 2015, despite not having used the data any more than usual. My credit limit has also been exceeded without the account being blocked, they continue to bill me above my credit limit?? What makes it even more questionable is the fact that because I have been billed more than usual I have used my data line even less to avoid this?. I have called MTN and all they said was that I used too much internet.....which is not correct taking the increase into consideration and using wifi opposed to my phones data. Really not impressed with MTN at all anymore. I feel their service has deteriorated and all they seem to do is increase their bills. I am currently at the end of my 2 year contract with MTN and will be moving to a new cell phone operator due to the apparent disregard for its customers. I am a loyal MTN subscriber and feel that the current state of affairs is just totally unacceptable.<br>