It is unfortunate that you are experiencing claim rejection. Not a good start for your relationship with the insurance company.
However, the good news is that you are covered by an insurance policy and now you know that you have a use for this policy.
Retail/Individual policies have a waiting period of 1-4 years for some diseases like diabetes, hypertension, cataract, piles, hernia, etc. Since these diseases are very common in the population and not very easy to diagnose at the time of purchasing the policy, insurance companies expect policyholders to wait for a few years before they could claim for those specific diseases. All other ailments (except excluded ones) are covered after 30 days of buying the policy. For example, if you get a fever, dengue, or meet with an accident, your policy will provide you relief.
Especially when one is diagnosed with diseases like diabetes, hypertension, heart ailments, kidney problems, etc., these conditions are going to have lifelong effects. Therefore, it’s very important to stick to your insurance plan because you have a higher probability of using the policy for the treatment of chronic conditions. It is not recommended to discontinue the insurance policy if the claim is rejected due to the waiting period clause.