Debited despite closing account

After paying off a credit card and settling the amount, I asked the call centre to ensure that they have indeed received the final payment which they confirmed. I was told it would take a few days for a confirmation of my account being closed. I received an SMS on Monday, 27th of July confirming that the account had indeed been closed and on the 28th of July, my account was debited. I called the call centre and the lady I spoke to told me that there was nothing she could do about the debit as there was a tracker placed on it. I would have to call again and ask for the debit to be reversed. She was very dismissive of this and kept telling me that I will need to just keep calling them to ask for the debit to be reversed each month even though I have settled the account. I just want my fund returned and my account closed! Is that too much to ask? Even the chatbot on the website just ended the query mid conversation.