DialDirect poor poor service

I logged a claim on 06 July 2018 because of a leak in my roof which damaged the entrance area, scullery and lounge area's ceiling. Shortly there after Dialdirect sent an assessor out to inspect the damage and cause. Very unprofessional handy-man company if you ask me and I was proven right. The assessor submitted a report to Dialdirect stating that the leak occured due to a lack of maintenance and DialDirect declined my claim. When I asked if the assessor is even in the position to make such a statement they said they will get a second opinion but this time from an approved waterproofing company. Why did they not sent them the first time? So the 2nd assessor came out and stated that the waterproofing used on the roof is a so called "pap and lap" which needs to be reapp**** annually. I am not a waterproofer myself so I did not know that. Anyway he also submitted his report to DialDirect and again my claim was declined as the leak is caused by a lack of maintenance and furthermore the 2nd assessor also stated in his report that my roof pitch is too low. Again I am not a roof builder and I bought the house like that. So I asked DialDirect again how does the 2nd assessor know my roof is too flat, how many degrees is it? And how much is it supposed to be? DialDirect's response again was he has not measured the pitch and they will send him out again to check the pitch. This is now the 3rd time that contractors need to come out and do the same inspection. Anyway, they came a third time and measured the pitch, which was too little according to building regulations. This final answer I received on the 17/08/18 over 1 months later - of course they declined my claim. I can accept that even though I do not understand how a normal person can know all of this, but anyway, so I ask them but what about the resultant damage in the entrance area, scullery and lounge area, are they at least prepared to repair that? Again DialDirect declined my claim as the damage resulted from the above stated faults. This, however, I do not understand and cannot accept. I do not expect them to rectify the structural fault of the roof but at least the resultant damage must be covered. Otherwise, I ask myself why do I even have insurance? I have done a lot of googleing on this matter and everyone says they should have covered that and then excluded these areas for reoccurring damage in the policy if caused by the same roof again.