Religare Health Insurance - Insurance reimbursement

I purchased the Policy in Feb'**, the day I purchased the policy, religare asked to conduct health check-up in their nominated lab which is fare enough as my parents age was above **'s. After testing there was no pre-existing disease found and they issued the policy mentioning the same(initial copy of policy along with test reports attached). Now, in **** my dad was admitted in hospital, against which I claimed the hospitalization amount which religare approved and transferred the amount in my account. During **** hospitalization period my dad diagnosed with diabetes which was very much mentioned in the discharge summary made by doctor and that very time and religare was aware about that.
Now, due to diabetes my dad operated in Dec'** and due to some miscommunication hospital staff wrote that patient is diabetic from last * years which is not correct and same was communicated to religare people via hand written letter from doctor itself and it was updated in the hospital records as well (all supporting documents attached)
As I can only attached one document, attaching the pre-health check-up details, I've more documents which proofs that religare claim is false.