Credit score being affected

So I decided to close my account with vodacom prematurely because of the lack of network service. I made the payment on the 23 April 2020, six days later on the 29 April 2020 I received an email from Vodacom advising that the account has been closed.

The on the 7th of May 2020 I receive an email from Vodacom with a statement advising of funds that are due. The amount is just under R23. Now what I dont understand is how was I quoted an amount and given 12 days to settle and then even though i settled within the 12 days, charges were added?

The account which has been closed almost a month ago still reflects as active on my credit report and thus affects me negatively.

I need this to be sorted as soon as possible. I am trying to buy a car and this will not help. I have finally severed all ties and business with Vodacom yet they still haunt my life.

I have anly ever had to complaint about this company. Can someone help or should I report to OMBUDSMAN.