Cant close my account

I tried to close my credit card account in the beginning of June 2019. Went to the branch and sign closure forms. They send it away. I received an email that i need to pay R138.74 before the 7th of June. I did pay the amount on the 6th and showed in my account. Went to the branch about 3 times and my account is still not closed. My ref nr is ***. Why cant they close my account