Bad service

I have been assisting my grandmother. She has paid off her car in 2000 and never received the Natis document that is registered in her name and she is selling the car. I have logged a call ref *** to send this document to the Absa Montana branch and the lady from the call centre said 5-7 working days. It has been two weeks now and still no document. The lady at the branch said that they don't know where the document is. And when we want to follow up on the reference number now the call centre does not want to help me.