Paid up my loan in January not updated credit pro

I have sent countless emails and have called RCS. I paid up and closed my account in January. Since then the RCS did not updated my credit profile with the Bueuro. There is an outstanding amount for some reason for more than 30days which has left me with a low credit profile and unable to apply for credit. Yet they've sent me a statement with a balance of 0.00. They do not update details and it looks bad for me now because I paid them upfront cash early settlement for loan. I need this fixed before I take legal action against RCS.