AMP is too quick to reject my claim not looking at the picture as a whole

AMP rejected my claim saying that the part that had broken is not covered under my policy, however Upon reviewing the circumstances leading to the damage, The tensioner in question malfunctioned causing it to exert excessive pressure on the cambox ultimately leading to its failure. When the tensioner broke, the cambelt slip which caused the cambox components to break inside. This is a clear case of mechanical failure rather than negligence or improper maintenance on my part as this vehicle was serviced at 210 000, it also has full-service history with VW. The part that malfunctioned still had 20 000 KM to go before needing to changed as per manufacturer guidelines (VW Guidelines) Furthermore, I have consulted with certified technicians who have confirmed that the malfunctioning tensioner directly resulted in the damage to the cam box. Their professional opinion aligns with my assertion that the root cause of the issue lies with the tensioner. I think that my claim should be reconsidered due to the above appeal that I am producing