Commands for text messages:
Block a user: block (their Yahoo! ID)
For example: block dairyman88
Block everybody: block all
Unblock a user: unblock (their Yahoo! ID)
Unblock everybody:unblock all
Reset a user: reset (their Yahoo! ID)
Send the command from your mobile phone to the following supported wireless carriers:
All U.S. Supported Wireless Carriers—92466
All India Supported Wireless Carriers—58242
TMTouch—17776
Singtel—428801
AIS—83140
DTAC—192466600
Globe—2258800
SMART—258600
Telkomsel—4246000