Billing System

I have a serious problem with the way discovery is billing my bank account.Firstly its the useless agents who are messing up my debit order dates.My policy started on the 25th of September 2015 and the wrong amount was debited from my account and i emailed the finance department to fix the transactions a lady named Matebelo Lepota responded on the 30 sep and i did instruct them to fix the transaction and debit the correct amount. They made the same mistake again this month of submitting on the wrong date and 21st instead of the 25th and no amount was debited.My understanding is that if the debit order day falls on a Sunday the transaction should go through the next working day.I am so much frustrated by this useless Matebelo Lepota and i do not personally think that she knows what she is doing there.This has penalty implications on my account and i have never had debit order problems with service providers before.I need someone senior to investigate all transactions and all communications and revert back to me.I do not have problems in with paying my premiums(i am not new to debit orders) but i have a big serious problem when the wrong amounts are debited from my account without