Incorrectly debited

DSTV disconnected twice. The consultant advised me that they debited half of subscription for one month and this month debited my full subscription and the other half for the previous month. Mind you my subscription was not disconnect for the entire month which i supposedly paid half for. When i go through my debited order no payment was missed or half paid for. I further asked if my debit order is set for 1100 hows it possible for them to debited half. And if i paid half my subscription for the month of May why wasnt my subscription suspended then ? The lady advised that she doesnt know... none the less i paid the amount I supposedly reversed and then later advised i owed because i paid half for via debit order. Working for a bank myself i have never heard of a service provider taking half of their debt order from a clients account.