[Your Name] [Your Address] [City, State, ZIP] [Email Address] [Phone Number] [Date] [Recipient's Name] [Recipient's Address] [City, State, ZIP] Subject: Apology for Not Crediting Payment on [Date] Dear [Recipient's Name], I hope this letter finds you well. I am writing to express my sincerest apologies for the oversight in failing to credit the payment made on [Date] against my account. I understand the inconvenience and frustration this must have caused you and assure you that it was an unintended error. Furthermore, I deeply regret any inconvenience caused by our failure to properly record the payment. Our accounting department has already initiated an investigation to rectify this issue promptly and ensure such discrepancies do not occur in the future. Please accept my assurance that appropriate measures will be taken to prevent a recurrence of this mistake. To rectify this error, I have enclosed a copy of the payment receipt, clearly indicating the amount paid and the date of transaction. It is my earnest request that you kindly review the enclosed documentation and correct the credit accordingly. I understand the value of prompt resolution and assure you that I have taken immediate action to rectify this oversight. Additionally, I will monitor my account closely going forward and promptly address any concerns that may arise in the future. I deeply regret any inconvenience and frustration caused by this error, and I assure you that this does not reflect our standard of service. We genuinely value our partnership with you and sincerely hope that you will accept our apology for this unintended disappointment. Should you require any further information or clarification, please do not hesitate to contact me directly at [Phone Number] or via email at [Email Address]. I am always at your disposal to address any of your concerns promptly. Thank you for your understanding and patience in this matter. Your satisfaction remains our top priority, and we will do everything in our power to rectify this situation swiftly. Yours sincerely, [Your Name]