DSTV disconnected - no answer provided

DSTV disconnected me because according to them I owe them money. I am on a price lock plan and they are supposed to be debiting money on my account monthly. The lady I spoke to on DSTV today did not have the full information and opted to cut my call. According to her they debited R549 and I am therefore liable for the balance. According to my records, they debited R584 and upon investigating she agrees with that. I wanted to find out why they deducted less than the normal instalment and there is no answer for that. How is DSTV disconnecting me when it is not my fault that they debited a lesser amount. DSTV did not even have the decency to phone and inform me that they debited a lesser amount. As I was engaging with DSTV I received an sms from them stating that they have stopped my account and in order for them to reconnect me I must pay R317.55. I am not impressed at all.