Nedbank's Failure to take Insurance claim seriously

We purchased a Bank-Repo property through Nedbank in October 2017. We took transfer in February 2018 and started paying our bond like good law-abiding citizens. Unfortunately for us, Nedbank refused to get rid of the defaulter and it became our problem to do so, having to lay out thousand of rands following the correct and prescribed legal procedures while of course also paying the rates and services (also amounting to thousands) for the dubious privilege of him and his family continuing to reside on our farm until 25/07/2018 when they called our lawyers and said - "you can collect your keys - we are leaving". We thought we were really in luck because instead of dragging out the process he was leaving on his own accord. What we of course did not know until we fetched the keys, that he had stripped the house of all its fixtures and fittings, irrigation system (including borehole pump), stove, all the security bars and doors, disconnected and destroyed most of the electrics in the house, removed switches, plugs, light fittings, socket boxes (and damaged the house wiring in the process), destroyed kitchen cupboards, built-in cupboards, etc and caused incomprehensible damage to the property, and ran up a municipal bill of almost R10,000 that same month which we too it seems, have to pay for. We reported this to Nedbank Insurance on the following morning, and they have proceeded for the last month to drag their feet, avoid calls, ignore emails and generally try skirt the issue telling us that they are not responsible for the damages. In our view, this is not acceptable. - The malicious damage was (and is) through their very own policy document their responsibility as the people living on the property were not exactly "our guests/known by us/or paying tenants.