To,
The Grievance Redressal Officer,
[Name of Insurance Company],
[Full Address of Insurance Company].

Subject: Appeal Against Wrongful Rejection of Health Insurance Claim

Policy Number: [Your Health Insurance Policy Number]
Claim Number: [Your Claim Number, if any]
Policyholder Name: [Name of Primary Policyholder]
Patient Name: [Name of the Patient]

Dear Sir/Madam,

I am writing to formally appeal the rejection of my health insurance claim, as communicated in your letter dated [Date of Rejection Letter], with reference number [Reference Number from Letter]. I am the policyholder of the above-mentioned policy, which is currently active.

My [Relation to Patient, e.g., son, self], Mr./Ms. [Patient Name], was hospitalized at [Hospital Name] from [Date of Admission] to [Date of Discharge] for the treatment of [Medical Condition/Diagnosis]. The total expenses incurred were ₹[Total Claim Amount].

Your rejection letter states the reason for denial as "[Exact Reason for Rejection as mentioned in the letter]". I believe this decision is unjustified and contrary to the terms of my policy and prevailing IRDAI regulations for the following reasons:

1.  [First Point of Your Argument. E.g., "Regarding the non-disclosure of a Pre-existing Disease, I would like to state that my policy has been continuously active since [Policy Start Date], for a period of over five years. Therefore, as per IRDAI's moratorium period guidelines, the claim cannot be repudiated on grounds of non-disclosure."]

2.  [Second Point of Your Argument. E.g., "The rejection letter cites policy exclusion clause X. However, a plain reading of this clause shows it applies to [Explain what the clause applies to], whereas the patient's diagnosis, as detailed in the enclosed discharge summary, is for [Patient's Diagnosis], which is a distinct and covered medical condition."]

3.  [Add further points as necessary, addressing each reason for rejection with factual, evidence-based counterarguments.]

To support my appeal, I am enclosing the following documents:
* Copy of your claim rejection letter dated [Date]
* Copy of the Hospital Discharge Summary
* Copy of the final itemized hospital bill
* [List any other key documents you are attaching, e.g., specific medical reports, copy of policy clause]

Given the above, I request you to urgently review your decision and approve the full claim amount of ₹[Total Claim Amount]. As per IRDAI regulations, I expect a written response to this grievance within 15 days.

Thank you for your prompt attention to this matter.

Sincerely,

[Your Name]
[Your Address]
[Your Mobile Number]
[Your Email Address]