Incompetence - CELL C/CFIBRE

In Feb 2019 I cancelled my fibre contract with CFibre (this was a huge problem on its own but evetually afte a few months they resolved that). There was an early cancelation fee of R3 849.84. This payment was taken via debit order on the 30th May 2019. To date this is not updated by Cell C - it reflects on my ITC reports and is currently affecting my home loan application. I have been asking then for two months now to please supply a statement or letter confirming this amount is paid up. They do not respond or assist in anyway. All I want is for them to do their job like they should have done 2 years ago by allocating the payment and updating my records why is this so difficult....