Summarize the following:
Text numbers are often abbreviated numbers, rather than 10 digit numbers. This is called the shortcode. Use your default text message app to create a new text message. This is the Sprint Free Message service that blocks text numbers. This tells Sprint that you wish to block the number. You can use the 5 digit shortcode or phone number. For example, " block <1234567891>." This code must be at least 4 characters long. This will block the number from sending you text messages.

Summary:
Find the number that was used to send the text. Write a new text message. Add 9999 as the recipient. Type the word block into the body of the text message. Add the number or shortcode in brackets. Send the text message.