Dear [Recipient's Name], I am writing to inform you that a duplicate payment has been made on [Date] for the amount of [Amount]. Upon reviewing my records, I have realized that the payment in question has been mistakenly processed twice, resulting in an overpayment. As per your company's policy, I kindly request a refund for the duplicate payment. I have enclosed the necessary documentation, including copies of the payment receipts, to support my claim. It is evident from these documents that the duplicate payment was indeed made and is not attributed to any other outstanding invoices or charges. I would appreciate it if you could promptly investigate this matter and process the refund accordingly. Please extend your attention to this urgent issue, as it has caused an unintended financial burden on my end. I trust in your professionalism and efficiency in resolving this matter swiftly. I understand that administrative errors can occur in any business, and I hope we can resolve this issue amicably. Furthermore, I would be grateful if the refund could be credited to the original payment method within [number of days] from the date of this letter. Should there be any further inquiries or requirements, please do not hesitate to contact me at [Your Phone Number] or [Your Email Address]. Thank you for your attention to this matter and your prompt action in rectifying the duplicate payment. I look forward to receiving the refund soon. Yours sincerely, [Your Name]