>> delete psrt-l [log in to unmask]
>>Invalid option - "WCCB". The valid options are GLobal, LOCal and TEST
>>(minimum abbreviations shown in upper case).
 
>Is there an alternative deletion mechanism other than editing the
>complete subscriber list?
 
Yes, replace the slash(s) w/ asterisk(s):
 
delete psrt-l WCCB*WCCB*[log in to unmask]