Icici Lombard Insurance - Health Insurance Rejection

I have had health insurance policy of ICICI Lombard since **** and have made regular payments and never put forward any claim. I contacted Dengue infection in August **** and got admitted in Medanta Lucknow. My health insurance got rejected on the grounds that i did not declare a pre existing disease. However I was diagnosed as "Reiter Syndrome" in **** treated for * year and off medication since ****.
It was declared during hospital admission because the doctor asked about any previous illness.
During policy inception their agent was informed about Reiter Syndrome to which he replied that it is not fitting the Pre- existing illness definition and so does not declared.
Mentioning the definition of preexisting illness as per Part II of policy wordings:
Pre-existing Disease means
(a) That is/are diagnosed by a physician within ** months prior to the effective date of the policy issued by the insurer or (b) For which medical advice or treatment was recommended by, or received from, a physician within ** months prior to the effective date of the policy or its reinstatement.
(c) A condition for which any symptoms and or signs if presented and have resulted within three months of the issuance of the policy in a diagnostic illness or medical condition.
As per this I was neither diagnosed nor treated within ** months of policy inception i.e. **-Aug-****. And so the agent did not find it necessary to declare,
The claim that i had put forward was for "Dengue management" which has had no correlation with the diagnosis and treatments of Reiter syndrome ** years back.