ADITYA BIRLA HEALTH INSURANCE CO LTD - Health insurance claim Denied

The insurance company is not approving my reimbursement claims, they are saying that I have not informed the pre -existing Illness of my wife.I have informed them at the time buying the policy, But they denying it.Further the have canceled my policy and sent my policy amount to me, without my permission.They have not shared/informed me the policy terms and conditions before buying the policy. They sent me after purchasing the policy along with the policy document.I have been asking the call recording of the conversation I had with their executive at the time of policy buying, they are not sharing it.The reason they are saying again and again is that I have not informed them the pre -existing Illness of my wife.