Health insurance rejected by saying reason of non disclosure, what legal action can be taken?

2 years ago

Dear sir, my brother got covid-19 on 16-05-2021 and got hospitalised on 20-05-2021. I applied for the cashless treatment and it got rejected by saying the non disclosure of pre existing disease .we told doctor that my brother taking medicines for chest pain from since 2 years then doctor asked about previous reports and submitted the reports since 2017..later we came to know that in 2017 report it mentioned as CRHD & I taken the policy on 09-06-2018 from cigna ttk (now Manipal cigna) . After checking all documents & discussion with my brother I understand that in 2017 my brother went hospital for chest pain then doctor suggested to take 2d echo then doctor written CRHD in prescription (as we not aware that time ) and told that don't worry use medicines for 2 months.we used same and stopped the medicines. As we don't know about CRHD at the time of taking the policy we not disclosed the same in 2018..we also went to hospital in 2019 for the chest pain then doctor told to use medicine for every day continuosly ,from that day we are using medicines daily and same is intimated during hospitalisation..please tell me shall I proceed legally for claim settlement on insurance company. Some of my comments are
1. We not aware or we don't about pre existing disease at the time of taking the policy & insurance company also not asked any previous health documents at the time of taking the policy.
2. We went hospital in 01/02/2017 and used the medicines for 2 months and stopped ..again we went in 22/01/2019..in 2018 and we have taken the policy.
3. We are admitted for covid-19 not for CRHD