Description Notify a customer of an error on their invoice and enclose a corrected one with this letter template. User [Company Name] [Street Address] [City, ST ZIP Code] [Date] [Recipient Name] [Title] [Company Name] [Street Address] [City, ST ZIP Code] Dear [Recipient Name] : When you placed your order, reference number [P.O. number] , we agreed on the price of $ [amount] . However, when we charged you on the invoice dated [Date] , we mistakenly undercharged you by $ [amount] . Enclosed is the adjusted invoice. Please remit a check/ cheque for that amount by [Date] , and accept our apologies for any inconvenience. Sincerely, User [Title] Enclosure