Simply send a text message back to 40404 with the following text:
STOP TWITTER
If for some reason this no longer works, then just add the 40404 number to your blocked caller’s list.
For me the “STOP TWITTER” text message did it. I was receiving text messages even though I didn’t have any mobile notifications set in my twitter account.
Hope this helps, and if it does say hi on twitter @gubatron.
Cheers