Receiving unwanted text messages on a Boost Mobile phone can be a real problem because the company charges for text messages whether you read them or not. If you are getting text messages from a specific number, you can block the messages by sending a special text message to the number "9999."
Open the text messaging editor on your phone. It's usually on the main menu of the phone under "Text Messages" or "SMS."
Create a new text message, and set the recipient as "9999."
Type the word "block" in the body of the message, followed by a space and the 10-digit number of the phone you want to keep from texting you.
Send the message.
Wait for a confirmation text message from Boost Mobile letting you know the block was successful.
You can reverse the block by texting "9999" with "allow," then a space and the number.