You have couple of options:
1. Approach Consumer Court and file a case against whom you issued cheques (Fortune Health Plus) making the insurance company also the party. Make everyone you interacted with from the agency a party. Keep it simple, say you issued cheques but they did not issue policy and due to which you are unable to claim medical insurance for your father's medical expenses. Also say that Oriental Insurance stated that that policy waswnot valid. This will be the fastest and the cheapest relief. You will have to explain to the court as to what were you doing all these days without approaching earlier. Give a proof that cheques were encashed but policy was not issued. Later policy was issued which was fake.
2. Register a fraud case (criminal) against the agent in the police station. This will put pressure on them. And with the police you say, a fake policy was issued, which the Oriental Insurance said was not valid. Here register complaint against all the people whom you have interacted with regarding the insurance. Do not give any original documents to the police. At the max, give a copy only.
3. Register an online complaint for free at http://corecentre.org/
Do 3rd point immediately. Then 1 and then 2.
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