Charging money with no follow up

I had a cybersmart account 3 years ago (changed because I was not happy with their service). I am someone who ensures I keep my accounts paid. I got a call from a debt collector yesterday informing me of an amount outstanding. I was more than willing to pay the amount, until I received the account statement. (The following is small amounts buy it keeps the principle). There was an amount of R48 originally that was meant to come of debit order. I did not know that there was a failure for it to come off and as such it got reversed. Since then, I have had multiple charges for banking reversals (I remind you that this was 2-3 years ago. I have had amounts for interest etc as well. How am I ever supposed to know that I have an amount outstanding if no one bothers to contact me. It is like Cybersmart are wanting to ***** money from me. I almost blindly paid the amount until I actually read the statement!