African bank duping me to pay more

I was offered 15% off my balance to settle it this month which I agreed to, but when I check my statement there is a sundry journal amount of R488 so I am getting this extra charge which I know nothing about so they are not giving me 15% off they are duping me into paying more because on top off paying 3000 on the 16th they are still going to deduct a debit order on the 15th which they say I agreed to and I have never done that. What I know is I am closing my accounts one a month so I become debt free and start saving