Operating in bad faith

Its been almost a year since Capitec last debited my bank account for a loan which I initially thought was paid up. I paid Capitec R 6000.00 odd rands and asked them to write off the balance of R 500.00 odd rands. They said they will get back to me. No debits were sent to my fnb account since then. I used my capitec savingd account to transact throughout and no attempts were made to collect using that account either. Now all of a sudden they have started debitting me without notice. No email no letter. Not even a letter of demand. I inquired this via an email they send two days ago stating that my account is behind. Some lady by the name of Suraya Imran responded in a very cheaky tone, saying they couldn't contact me and its my responsibility to update my details with them. How do I update details for an account which was meant to Have been closed a while ago. Why didn't they email me, why didn't they phone me at work. This is a ploy to increase their revenue by stopping collections when there's a small balance left and when they are satisfied that the interest have grown, the they started debitting. This is the fourth case I have heard of. Exactly the same. So when you guys do decide to contact me get me your most senior person. who will have all the facts of my account in front of them. I need answers period. Enough of this ****.