Can't cancel my contract

Every few months I get charged for Data despite me buying data bundles. The most recent being that I bought bundles in April and still got charged R9000 odd for data used between the 20th and 27th April. I have requested my April 2015 invoice to prove this to no avail, the online portal shows all statements except the April 2015 one. I have made calls I have received e-mails saying the device used the data but absolutely no recognition that it was in fact covered by my bundles. Numerous emails have not helped, numerous calls have not helped. My contract with MTN is now over for two months I want it moved to prepaid so i can port to another network there is no way I am staying with a network that causes unecesssary drama with incorrect billing not once not twice but FOUR times!!! Your staff are unhelpful and its high time someone in your business actually sorted out these billing issues as I am not the only one by the looks of things. I do not want to spend another month on contract with you guys, your fees are too high, your billing is *****ed and i am tired of being disconnected for nonsense. Sort it out<br> <br>