To, Name of the recipient: ______________ Designation of the recipient: _____________ Name of the recipient company: ____________ Address of the company: ______________________________ Dated: __________/___________/_________ Subject : ________________ Dear ______________, Please refer to your letter ____________[date] regarding ___________[ invoice No.], wherein you have described about the billing error in the invoice mailed to you. In evaluating our records and checking your __________[ account number ], our Account department have located the error. Meanwhile, we have corrected the error and the amount will be credited in your next bill. We appreciate your business and apologize for the mistake and assure you that, such error will not occur again. We hope to offer our best possible services as always. For any assistance in future, you may contact me at _________ [phone no.] Regards, Name ...