Dear [Customer's Name], We hope this letter finds you well. We would like to sincerely apologize for the accounting error that occurred in your recent transaction with us. It is important to us that we rectify this issue promptly and provide you with the best possible customer service experience. At [Company Name], we strive to maintain the highest standards of accuracy and accountability in our financial records. Unfortunately, in this instance, an inadvertent error was made during the accounting process, resulting in an incorrect amount being charged to your account. We understand that this mistake may have caused inconvenience and frustration for you, and we deeply regret any distress it may have caused. Rest assured, we have conducted a thorough investigation into the matter to ensure that similar errors do not occur in the future. To rectify this situation, we have already credited the incorrect amount back to your account, and we will soon be issuing a corrected invoice reflecting the accurate charges. We understand the importance of accurate accounting and the impact it can have on your business, and we assure you that we have taken immediate corrective measures to prevent such errors from happening again. In addition to rectifying the accounting error, we would like to extend a gesture of goodwill to you as a token of our apology. We will be offering [specific compensation or discount] on your next purchase with us. We value your continued support and want to assure you that your satisfaction is our utmost priority. Once again, we apologize for any inconvenience caused by this accounting error. If you have any further questions or concerns, please do not hesitate to contact our customer service team at [customer service phone number] or by email at [customer service email address]. We are committed to resolving this matter to your complete satisfaction. Thank you for your understanding and patience. We greatly appreciate your continued partnership with us. Best regards, [Your Name] [Your Title/Position] [Company Name] [Company Address] [City, State, ZIP] [Contact Information]