Mobile operators require that content providers allow you to stop any service at any time by texting STOP to the shortcode from which the content is coming. To stop a service...
* First, look at your phone bill and/or one of the messages that you don?t want for a phone number. Most often, this is a 5-digit number, such as 99099
* From your phone, create a new text message containing only STOP
* Enter the phone number from the unwanted message.
* Send the message

Within 24 hours, the offending sender must stop sending messages to you on that number.
To stop all services coming from a vendor on one shortcode, text STOP ALL.