Insurance Claim Denied!!

I have lived in my house for 9 months and discovered that my roof was leaking. I submitted the claim (16/009391), a contractor was sent to assess and provide a quote. After 2 weeks of no response or feedback, I called STD Bank's Call Centre and was told that the claim was denied due to poor workmanship. So now I'm kind of confused. What am I paying homeowner's insurance for if they don't cover things like this? I certainly did not \build/install\" the roofing and the house was bought on auction, so pursuing the previous owner is not an option. And if the roof is not repaired and there is damage to the interior of the house where the contents need to be replaced due to water damage e.g. wiring, appliances, carpeting, damp and mouldy walls, should I even bother claiming or should I assume (based on this experience) that they are going to deny my claim AGAIN anyway??? <br> Once again: What is insurance for if not for matters like this??? "