Nedbank Insurance payout

I bought a house through nedbank last year December, moved in on the 24th of December 2018, second week in the house the roof was leaking, contacted nedbank nothing happened, all year round when ever it rain I need to look for buckets as if I'm staying in a shack, bought roof sealents and stuff but this just doesn't shop gets wors with every rain, my couches are getting wet from this and carpet too, fast forward to date, I again contacted Nedbank home insurance they advise they sending someone to have a look, an assessor came and look at the roof and advise we will be contacted, now I get a call that they won't fix the roof as it's poorly maintained, when we bought the property they sent an inspector to look at the place,.

Why didn't their inspector see the roof is not up to standard, now they refusing to fix the roof I'm not even a full year in the house then I have to redo a roof, I'm paying a fortune for that loan I can't be paying to fix the roof, I have four kids asking me to move back to the flat we were renting because they can't stand all thing running around everytime it rains, and ask me what kind of house did we buy they don't even want to have their friends over when it rains, this is not how I imagined my first house will make me feel like this, it so frustrating. Please assist nedbank should fix this roof their inspector should've seen this and disclosed this then I wouldn't have baught the property if this was the case