Bad service

I am disappointed in the service received from Discovery Insure. I did a quotation for vehicle finance and accepted their cover, however, on the same day I received a better offer from Mercedes Benz Alexander Forbes consultant. I contacted Discovery Insure to cancel the cover but their cancellations department did not answer my call after numerous attempts. My account was debited and I reversed the payment as I had not been able to get hold of anyone to assist with the cancellation. To my surprise my credit report was updated that the insurance was cancelled due to non-payment. This is falls information, my cover was canceled because I git a better offer. Alexander Forbes updated my account for the same month as ok- proof that I did in fact take up cover with them. I I have tried to sort this out with Discovery and one of their assistants acknowledged that they can see that I tried to get through to their cancellations department but was unsuccessful but did not assist. I would like this incorrect information removed from my account.