Nedbank Insurance is despicable

On 2 April 2019 sewerage water was gushing out of my toilet for approximately 3 hours and flooded my house. I logged a fault with Joburg Water because we couldn't find a blockage in our system. Joburg water came out on 3 April 2019 and confirmed that my drain wasn't blocked. I was initially told that the manhole to which the house is linked had a blockage. It then transpired that Joburg Water had given the engineers installing toilets at the nearby Zamimpilo Informal Settlement permission to connect their sewerage system to that of the residents. I contacted Nedbank Insurance and after a week I got a call from a very rude employee telling me the claim was rejected. I was trying to explain to her that the actual cause was as a result of the connection but she very rudely told me the claim is rejected and hung up. We have been with Nedbank Insurance for over 20 years and only had a claim for a leaking geyser in those 20 years. I am disgusted with the service I received. The house is inhabitable due to the smell. The event not insured is so vague. I was told by this very rude individual she would email the rejection letter and I'm still waiting for it because I do intend to drag them to court!