Receiving unwanted text messages on your cell phone is not only annoying; it's expensive, since you pay for every text message - whether outgoing or incoming. Mobile spam or m-spam, as it's known, must be viewed before you can delete it so you can't ignore it or pass it by as you can with email.
Blocking text messages is possible, but blocking only specific messages is not (at least not yet), and cell phone providers do not advertise the blocking options they provide.
To make it even more difficult, each company has its own method you must employ. Cell phone companies lose money when text messages are blocked because they can't charge you for those messages, so while you can usually find a place to tell your company to block text messages, you're going to have to do some sleuthing.
AT&T and Verizon Wireless offer a solution that works for the most part, although spam may occasionally slip through. The reason is that spammers usually send SMS text from an internet browser. Since messaging from a browser is free and anyone can do it, it keeps their costs down and helps keep their identities hidden. AT&T and Verizon use this technology to allow their subscribers to block text messaging that originates from a browser instead of a cell phone.
Other providers do things differently. If you have a T-Mobile account, you can block all messages sent by email, from both browsers or cell phones, except for messages from T-Mobile. For Sprint, you can block certain numbers from sending text messages to your cell phone. That helps, but you can't keep the first cell phone message from getting through.
How to do it
Log in to your account and click on the "Preferences" link. From there you'll find text message blocking and alias options. To block by alias, you're allowed to replace your cell phone number with an alias name. You then give this alias to contacts you want to text you. It works like a forwarding address, so you can use it whenever you like. Since it's not a number, the spammers can't guess it.
Log in to your account and look for "Text Messaging"; then click on "Preferences". You'll see a link called "Text Blocking", where you can create an alias.
Again, log in to your account. Click on "Communication Tools". You will see an option for you to block text messages. Theirs may be the most comprehensive system, since you can also block a cell phone text message that contains certain phrases or messages that are sent to your number instead of your cell phone email account. You can permit text messages to be sent to an alias here, too.
Log in to your account at Sprint, then click on "My Online Tools" and look for "Communication Tools". You will see "Text Messaging". Click on the "Compose a Text Message" link, then look for "Text Messaging Options". Once there, you will see "Settings and Preferences". Enter the phone number or email address you want to block. You can also block an entire domain.
Other providers have their own ways of dealing with blocking cell phone text messages, so if yours isn't here, go to your provider's customer service department and have them explain how to do it.
It may take a little effort to block cell phone text messages that you don't want, but it isn't impossible and it can save you money as well as peace of mind.