Disinterested

This is the most arrogant and disinterested organisation I have had to deal with.. According to them I app**** for a R20 000 credit facility or loan or whatever.. Bottom line is I did not apply.. Anyway to cut a long story short. I asked them for proof of this application with my signature which they have to date been unable to produce but maintain that the loan/credit was never approved anyway and does not exist(easy way out), however, this account remains on my credit profile as an active account which affects me negatively. All requests for a letter of acknowledgement that the account does not exist fall on deaf ears and the account remains active on my credit profile.. Now I ask you.. What is my next step with these arrogant *****s.