4 attempts and still no resolution

I called MTN call centre 6 times so far to report a problem i have been experiencing for over 2 months now! My airtime is being used even though i still have data available! I recharge my account with R29 and not even 10 minutes later, all my airtime is gone! i called the call centre 6 times in total, held on for several hours in total, spoke to useless, *********** agents who made promises and never delivered! logged more calls because no one knows whats happening and still, 2 months later i still have the same problem! i have no choice but to load airtime because i am stuck with this useless service provider until my contract ends! i want MTN to sort this out immediately or i will resort to going to an MTN store or head office and causing a scene because clearly calling the call centre has not helped me in any way! i am at my wits end with this pathetic service provider! i want my money back or i want out of this useless contract!!!! resolve my issue or i will be taking this further! i expect answers from someone (if there are even any competent people at this company)