F & A CSI User Manual related Western Union Cheque Payment transaction as well as Stamp / Postal Stationary and IPO Indent procedure from Head Post Office to CSD through SAP. March 05, 2018 CSI , WUMTS F & A CSI User Manual related Western Union Cheque Payment transaction as well as Stamp / Postal Stationary and IPO Indent procedure from Head Post Office to CSD through SAP.