Unwilling to understand and double deductions

Roughly a month ago I've changed from Nedbank to FNB, in the process I had to change debit orders of which one is a Nedbank personal loan. I've made arrangements with Nedbank to do so. They've deducted once of the old Nedbank account and now randomly again in same month from my FNB account. After having 4 different phone calls regarding the debit order banking details changing. Call Reference number: 209121 as well as ***. I can mention to ladies hoe attempted to help: Lamize and Michelene. Anna is their supervisor but is never available for contact or comment.