Mbd a eligible nsfas debt collector?

I have been making payments of my Nsfas student loan through Mbd solutions for 3 years now while I was still on contract. I recently got a permanent post and i requested them to please change my payment option from a monthly debit orders to a persal deduction. It has been months now and nothing has been done regarding my request. I only receive messages to please pay now via EFT. Does nsfas even communicate with these debt collectors? How should we trust their eligibility when they cannot even honour a simple request. I do not refuse to pay but only request a change of payment method . I dont even understand how I was even handed to debt collectors at first cause I never refused to pay, regardless a deduction in my persal is for my convenience.