Debit order on Settled account

I am having a problem. I settled an account that was supposedly handed over to Legal by African bank. Mind you African bank is sending me statement month in month out for this same account, they debit my account monthly for this very account as well. Understanding that the account being handed over to Legal has a bad impact on my credit rating. At the End of August I decided to Liaise with the Lawyers to settle the account we made arrangements and I settled the account. Funny enough a debit order ran from my account on the very same day for that account from African Bank. I decided to go to the bank to inform them that their Lawyers haven't sent me any Paid up Letter for the account I shared my frustrations with them and asked them to assist me in settling the issue of getting the paid up Letter because Norman Bissett was giving me the run around they agreed and asked me to mail them proof that I've settled, I send confirmation on the 11/09/2017. the whole month no feedback or nothing. To my surprise the End of the Month African Bank Debited my account account again for that very same account. Can I please have somebody save me from these ********. Can they stop debiting my account and provide me with a Paid up Letter because this issue is affecting my life