Lack of internal communication.

I have a student loan with Standard bank, where my father was surety and guarantor. He passed away in December 2014, and because he signed for death insurance, all debt should be written off. In order for this to take place, certain documents were longed for by Standard bank. I have sent two copies from home, one from a branch itself and another from the people at ABSA dealing with my dad's will, in a time period from February up until now. STILL they call, send letters and email me, threatening to take legal action against me if I don't pay. Upon contacting their department handling matters concerning the deceased, nothing was found on record. Do the staff at Standard Bank follow procedures to get documents from point A to B? I am sick and tired of this story dragging and reaching no specific point.