ABSA trying to force me to make minimal installments to get more interest out of me

I have a small personal loan from Absa and trying to pay it off faster, I phoned 3 times and each time they assure me that the debit order amount will be changed to my desired amount and then at the end of the month, surprise - nothing changed.

I even went to one of the branches and the branch manager phoned on my behalf, they assured me it would be changed as per my request and sure enough again nothing happened. Then I was contacted by the collections department and they said they will fix it, again nothing happened.

The only reason I can think that this is happening is because it is in Absa's best interest for me to pay the minimal amount each month, therefore paying more interest to Absa. After trying to fix this so many times and having no results I am quite tempted to change all of my accounts to a different bank, this is completely unacceptable. If you guys cant get my debit order right after 5 attempts I have little faith that a 6th attempt will help.