How to enforce insurance claim

My vehicle had a breakdown. Used authorized service to tow the vehicle. to authorized service center. They identified the cause i.e. rat bite which lead to some damage. Corrected the same. But repeatedly insurance technician are not able to see the rat bites and the taping that is done. and so denied my claim citing the same reason. Took the vehicle on their request again to service center. and everyone there were able to see the rat bite and wire taping done. and insurance people also saw the same. But again next day I get a mail of claim denial citing the same old reason that technical people appointed from insurance were not able to confirm the rat bite. Which is ridiculous and is harassment to me. Please suggest the way forward.