Duplicate original NaTIS certificate required

I emailed to request what was required for me to get a duplicate original NaTIS certificate from the bank. The person emailed me back saying a request in writing and copy of my ID and payment should be made. I have sent all of this to discover today there is additional information required. The email is sent with no name or contact number of a person and I am now sick and tired of going backwards and forewards with what is required. I financed my car through Wesbank ten years ago and am still the owner of the vehicle. All I want is the duplicate papers as they have gotten lost. I need someone to advise what all I need as I have now paid for these documents to be couriered to me urgently....!!!!