Installment increase because of changing debit order dates

I called absa and spoke to Carel in absa and vehicle finance.i got a new job and tequested them to shift dates for my debit orders and i was told that the installment will increase.i am dissapointed at the way the operate because i am not skipping payment but simply changing debit order dates.i tried locating complaints on their website they have made sure we cant access complaints.