Loan agreement gone wrong

I am saddened by the way you Nedbanks personal loans department has repeatedly a promise we signed on.. I took a loan last year around November at Nedbank, the agreement was that they would set a debit oder weekly deductimg their amount because I earned weekly. Everything was smooth sailing until I received an Sms from them in November requesting to deduct twice the amount for the first 2 weeks of December so that on the last 2 weeks they don't get to deduct. I immediately called and requested them not to do so because most of my debit orders are weekly and in them doing so it would affect my other debit orders. They agreed they will continue with debit agreement we started of with.

Last week they then go and do the complete opposite of what I requested, which was deducting twice the amount, I called and asked for an immediate reversal because I had called and the told me to wait for 4 working days, which is completely unfair given the fact that I called and asked them not to do that. I then asked the consultant that assisted me to please ensure that it does not happen the following week and she assured me it wouldn't and it did. I am absolutely upset with this department because such mistakes are ones that tarnish our credit scores and I then still have to suffer with the little amounts that are charged on my account for a reversal of a debit order an transaction fees