Warped Velux Window?

[glasgowok]

In late summer 2010 I went onto the roof to repair a tv ariel and in the process I stood on the lower part of the window frame and caused two dents, at first my insurers were going to pay for the repair but when they recieved a higher than expected quote for the job they backtracked and are now refusing to pay because they say the 'warp' was caused by bad workmanship. Is it possible that heat, extreme cold or high winds could have made things worse after my initial damage or my damage had nothing to do with it and it was badly installed?

There is a picture of the other window which looks ok to my untrained eye.



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