Travel insurance Claim

i have taken out a policy for travel insurance. this was done with Regent travel insurance our flight was delayed in Chennai and we lost more than 5 hours . I sent my claim any now the insurnace wants us to provide proof so we send the the travel itenary which state the original boarding time and a copy of the new boarding pass with the actual time. now they dont want to pay us the insurance wants a letter from the airline which is Air India and they want to know what why was he delay. I informed them hat I made the claim and its there duty to investigate the matter this matter is stil pending since october when we returned herewith my claim Claim number CRE04061-11-17/SOMAI Harilal