Storm damage not covered

We've bought a house through Nedbank. They awarded us a loan for the house and we opted to get house insurance through Nedbank. A year later there was a huge storm (abnormal amounts of water came from our roof and into our yard). Water came into our house - causing damage to our wooden floors and kitchen cupboards. We contacted Nedbank and they sent an accessor. He decided that our house was planned badly and the roof had wear and tear. The accessor also mentioned that because of the recent storms they've had numerous claims and they are not willing to pay all of them. My question is - Nedbank had to come to the house to look at the house and the roof in order to grand us the loan. They never mentioned that the house or the yard was designed incorrectly or that there was an issue with the roof – if they did we would obviously not have bought the house, but now that we have damage due to a huge storm and abnormal amounts of rain they won't pay for the damage as it is our fault according to them.