Destroying my financial status

I have had an account from December 2019, I have paid diligently every month more than twice the required amount or instalment. Recently Jet under went a business rescue and sold their credit to a debt collection company Norman and associates under the Nimble Group.

It took me years to work up and get a healthy credit record, but this two companies has messed my credit rating ever since the buy over, my credit records shows no payment from September 2020 yet I have been paying more than my instalment every month. Now I am wanting to take a bonus and pave my life buying my first property and I can not get the bond I require due to their mess up. None of the two are updating my payment since September 2020, I think I will take it up with the Ombudsman and my legal council.