OPEN MAIL AND PREPARE REMITTANCE ADVICE. A mail room employee opens envelopes containing customers’ payments and remittance advice's. Remittance advises (see Figure 4-10) contain in- formation needed to service individual customers’ accounts. This includes payment date, account number, amount paid, and customer check number. Only the portion above the perforated line is the remittance advice, which the customer removes and returns with the payment. In some systems, the lower portion of the document is a customer statement that the billing department sends out periodically. In other cases, this could be the original customer invoice, which was described in the sales order procedures.