What do we do the add pre existing disease in ICICI Lombard now and my policy is almost renewed thrice

I was customer of Oriental Bank of Commerce. Being a customer of Oriental Bank of Commerce, Oriental Insurance Company provided Group Health Insurance Policy and inception date was 04-05-2015. My policy with them continued till 03-05-2021 without any break. Because Oriental Bank of Commerce merged with Punjab National Bank, Oriental Insurance Company discontinued that policy from 03-05-2021 onward. Being a customer of Punjab National Bank, I approached them, and they migrated my Group Health Insurance Policy of Oriental Insurance Company to Star Group Health Insurance Policy for customers of Punjab National Bank from 04-05-2021 to 03-05-2022.  As All my policy periods were continued from 04-05-2015 till 03-05-2021 with Oriental Insurance Company, Star Health Insurance given me the benefit of pre-existing disease waiting periods being waived because of continuity (They mentioned it in Policy Document too). They reimbursed my 1st claim of 15 July to 22 July 2021 (Non Empaneled Hospital) and Cashless claim of 16 December to 19/12/2021 but denied reimbursement of 19/12/2021 to 26/12/2021 with the excuse of pre-existing disease even I directly shifted from cashless hospital to non-Empaneled Hospital for same problem because Empaneled hospital having been less facilities.  Here I want to address that I was discharged from Cashless Hospital, on request, to get treated in Higher Hospital and treatment was in continuation of previous cashless hospital to new hospital. So, sir, please guide me accordingly as my correspondence with them is not fruitful.

At the time of renewal of policyif we declare some disease which is not there at the time of inception of policy, will the premium will increase for the disease or it will increase accordingly as per the renewal time

Is it necessary to declare the disease at the time of renewal of policy which is not before at the time of inception

my policy number was taken on 19 February 2021, in the first week of March 2021 suddenly my blood pressure increased, due to which the doctor asked me to undergo angiography. After that the doctor asked to do angioplasty immediately and thus on 18 March 2021 I got angioplasty done. Now I am completely healthy, since my illness occurred within 31 days of taking the policy, company agent told me that there is no provision to cover any health related problem within 31 days. Company agent told me that there is no provision to declare any illness midway. Now I am completely healthy. Company not include my above mentioned health condition in my policy. And compny given me reply "Dear Mr. Jain, We acknowledge the receipt of your mail. With reference to our previous telcon, this is to inform that any disease or ailment/illness if found after inception of policy. It is not required to disclose under policy. But if you still wish to disclose the disease then kindly find the attached PED inclusion form, fill and submit us for further evaluation. Note : To note the disease in the policy PED form is mandatory. We request you to provide the Medical reports/ Discharge summary /any relevant /First consultation paper / medical document of the said procedure/diagnosis, which shall be kept for our reference. " What can I do.