Subject: Apology for Not Crediting Payment — Acknowledgement and Resolution Dear [Recipient's Name], I hope this letter finds you in good health and high spirits. I am writing with sincere apologies for the oversight in not properly crediting your recent payment to your account. This mistake was in no way intentional, and we regret any inconvenience it may have caused. Upon discovering the error, we promptly initiated an investigation to understand the cause and resolve the matter efficiently. Our records indicate that your payment was indeed received; however, due to an internal oversight, it was not credited to your account as it should have been. We understand the importance of ensuring accurate transactions and the inconvenience this discrepancy may have caused you. Please accept our sincerest apologies for any inconvenience, confusion, or frustration you may have experienced as a result. To rectify this situation, we have taken immediate action to credit the full payment amount of [amount] to your account as of [date]. We have also put measures in place to prevent a recurrence of such incidents in the future. We genuinely value our relationship with you as our esteemed customer and assure you that your satisfaction and trust are of utmost importance to us. Rest assured that steps have been taken to ensure that our payment processing system is thoroughly reviewed and closely monitored to maintain its accuracy and reliability. Should you have any questions or concerns regarding this matter, please do not hesitate to contact our customer service department at [phone number/email address]. Our dedicated team is readily available to address any queries you may have and provide further assistance. Once again, we deeply apologize for the omission and any inconvenience it may have caused you. We genuinely appreciate your understanding and patience. Our commitment to providing outstanding service remains unwavering, and we assure you that such incidents will not happen again. Thank you for your continued trust in our business. We value your patronage and look forward to serving you with excellence in the future. Yours sincerely, [Your Name] [Your Title/Position] [Company Name]