Poor momentum household insurance

My life policies and insurance products have been with Momentum for the last thirty years . This was followed by taking out my householders policy with them as their rates were cheaper than what I was paying. With the the interrupted supply of water in my area ,we experienced a build up of pressure , resulting in the flooding of my house .After suffering substantial damage to well kept house Momentum does not want to honour the claim citing negligence. My vehicle a five series is also insured with them and God forbid they take the same stance in the event of an accident. Public be cautious with with cheaper premiums and poor delivery.