Cell False Report on Credit Report

I have been trying to work with Cell C for the past 20 days to resolve an error caused by their website not working. After expressing to them that their mistake had detrimentally affected my time-sensitive vehicle finance application, I paid an additional ZAR8,986.70 (now totaling ZAR22,466.75) in payments made by me for a contract that costs about ZAR2,500 per month. I paid the additional amount while they (still unsuccessfully) searched for the website payments so that my account would reflect that it is in good standing and I can carry on with my vehicle finance - the agent told me that it is impossible for Cell C to generate a statement of account and I would just have to wait for my statement on the 6th of March. It is ridiculous that they were not willing to even manually type up a letter stating that my account is in good standing.

I need to emphasize that all of this was caused completely due to their website payments not being allocated despite the payment being made through my account profile.

The agent has also refused to share any reassurance with me that they will correct the info that they shared with the credit union. They will not correct the information that currently falsely shows that I made late payments. I will have to dispute this directly with the credit union and escalate this to the ombudsman, as I am not sure how to navigate a company that is unwilling to correct their errors and using the stall tactics of sending me from one clueless agent to the next.