Blocking the Serial Numbers

Hi,

While transfering the material to distributer place, materials (5 Qtys.) are lost, these materials (5 qtys.) has been assigned to 5 Serial numbers. In IQ03 the status of these 5 Serial numbers are ECUS. Now the user wants to Block these Sr. nos. in SAP as the material is lost. We can Deactivate these Sr. nos. in SAP. But i think it has no meaning, if we are BLOCKING these serial numbers when the status is ECUS? Plz. let me what we can do?