Old Mutual insure not paying.

I insured my vehicle with Old Mutual through a consultant PSI after a few years I had an accident and the window of the canopy was knocked out by a generator that somehow moved during the transport. I was told that the canopy of the vehicle is seen as extra and should be specified in my policy. I was never told that when I took out the policy, how should one know that. I bought the vehicle second hand and the canopy is colour-coded the same as the vehicle. I am very unhappy about the fact that they now refuse to cover the cost. I layed a complaint but get no reply from them