Cost that's not being disclosed

Had a burst pipe inside the house which caused half the house to flood as we were not home. Old Mutual Insure is my insurance for building and contents. From start they were excellent with service and assistance until the claim was approved which took a week. I have to pay a percentage of the approved amount as it is more than the min excess payable. I am fine with that except, when I asked for the breakdown of the costs approved to see how my excess was calculated, That's not allowed!!!!! I am paying the excess, I should have a right to know how it is being calculated. By having this information, it also helps me know what the contractor should be doing. This is definitely not acceptable from a clients point of view