Debited before agreed date

Hi Good day

I have to say that I am a bit disappointed with nedbank after making arrangements to pay off my loan spoke to a advisor that confirmed that my loan payment debit order will be deducted on the 27th of August when I get paid which was what I agreed to I have been waiting more than 3 months for my uif money times are tough i am barely getting by daily when the payment finally reflected in my account nedbank debited my account I called numerous time to have the money reversed because it is not what I agreed to I emailed the complaints department and no feedback