Incorrect debit order

Good day I would hereby like to put in a complaint regarding an unfair treatment by MFC, a few months ago I requested my initial installment to be increased to try and reduce my term, that was done successfully with no hustles same day, however as I work on a commission my salary was low for me to afford from last year November, I then called in to go back to my initial installment however that has not been done ever since last year. I keep getting promised that a team leader will call me but I never get called.