Dear [Customer's Name], We sincerely apologize for the recent accounting error that occurred on your invoice [Invoice Number] dated [Date]. We understand the inconvenience this may have caused you and want to assure you that we are taking immediate action to rectify the situation. At [Company Name], we strive for excellence in all aspects of our business, including accurate and reliable accounting procedures. Unfortunately, in this instance, our internal checks and balances failed, resulting in this error. We take full responsibility for this oversight and are committed to ensuring it does not happen again in the future. Upon thorough review of your account, we have discovered that an incorrect amount was charged for [Product/Service]. The correct amount should have been [Corrected Amount]. To rectify this error, we are initiating a refund of the overcharged amount, which will be credited back to your account within [Reimbursement Timeframe]. We sincerely apologize for any inconvenience caused by this mistake and assure you that the corrective measures are being taken to prevent any future similar errors. Furthermore, we are implementing additional training and procedures for our accounting team to enhance our accuracy and minimize the likelihood of such errors occurring again. We understand the importance of your trust in our company and want to assure you that we value your business and loyalty. If you have any further questions or concerns regarding this matter, please do not hesitate to contact our customer service department at [Customer Service Phone Number] or via email at [Customer Service Email]. Our dedicated team members are prepared to assist you and provide any necessary clarification. Once again, please accept our deepest apologies for any inconvenience this accounting error may have caused you. We appreciate your understanding and look forward to serving you in the future with the utmost accuracy and professionalism. Thank you for your continued support. Warm regards, [Your Name] [Your Title] [Company Name] [Company Address] [City, State, Zip Code] [Contact Information: Phone, Email]