Billing Gone Wrong

So i added a 3GB data contract to my current account as a seperate sim card.<br> It is supposed to cost me R189/ month on top up, meaning that when i reach the 3GB of use, i should get cut off.<br> <br> I however was not cut off for the months of June & July and and have now racked up an additional bill of R1446,90 in PSD Calls that i should not be able to make!<br> <br> It is not my responsibility to stop my data when i reach my limit, I pay you, MTN, to do that for me.<br> <br> I have opened 3 billing enquires through the MTN branch near my house, 2 of which have been responded to as either correctly billed, or the query was logged in the incorrect place.<br> <br> I was billed far too much money at the beginning of this month for something that is not my issue.<br> <br> I want all the PSD costs, all R1446,90, credited to my account, nothing more, nothing less.