Over charged

This company is ripping customers by charging extra that no one can explain. I have called DSTV numerous times for some answers 2 months later no one has bothered to contact me to explain why am I paying extra on a monthly bases, every time I call in an agent give conflicting reason what the extra charge was for and each promise to log a call to finance to have it sorted but hey to date no one could be bothered. When you enquire via their app how much you owe its always less than the debit amount. How is this possible?