Dear [Customer Name], I hope this letter finds you in good health. I am writing to sincerely apologize for the oversight in not crediting your payment promptly. We deeply regret any inconvenience or frustration this may have caused you. At [Company Name], we take pride in our commitment to excellent customer service and timely payment processing. Unfortunately, due to an unforeseen technical glitch in our payment system, your payment was not reflected on your account as expected. We understand the importance of prompt crediting and assure you that steps have been taken to prevent such errors in the future. Please rest assured that the oversight has been rectified, and your payment has now been credited to your account. You should see the updated payment details reflected in your next statement. We understand the importance of accurate and efficient payment processing, and we apologize for falling short of these standards in this instance. In order to make up for the inconvenience caused, we would like to offer you a [discount, voucher, or gift card] as a token of our apologies. We value your business and want to ensure that your experience with us is nothing short of exceptional. Once again, we deeply apologize for this error in payment processing. We appreciate your understanding and ongoing support as we strive to provide you with the highest level of service. If you have any further questions or concerns regarding this matter, please do not hesitate to reach out to our customer support team at [contact details]. Thank you for your patience and continued trust in our company. Sincerely, [Your Name] [Your Title/Position] [Company Name]