Wall damaged due to floods and claim rejected for 2.3m high wall which was build 20yrs ago!!!

Recently due to the heavy rains and flooding my communal wall that is shared with my neighbor who has been living in his property for almost 20years collapsed. Only my side collapsed as his wall is made from stone and not bricks. His electric fence also got damaged and is still not working which is a security risk. FNB declined my claim stating my wall was to high, my question to FNB is why send an assessor to assess the property for insurance but did not alert me that my walls that have been build decades ago is too high. They gave me a premium and i accepted the cover but when its time to claim for damages then they quick to find ways to reject your claim, yet they do not take any responsibility for their stupidity or incompetence of assessing properties. Apparently my wall must be shorter then my neighbors so everyone can see!!!