How to Block Mobile Phone Spam

Just when you think you've got junk mail and e-mail spam under control, you might start getting unsolicited text messages on your mobile phone. This can be especially irritating because you normally can't delete a text message without opening it, and in some plans, you might get charged for every text message you receive!
The most important thing you can help stop text message spam is to reporting it to your carrier. Carriers shut down and block spammers, often suing the worst offenders. But they need you to tell them who is spamming and what is in the spam messages. To report text message spam, forward the text message to short code 7726 (spells 'SPAM' on the keypad).
You can try blocking spam directly using steps listed below, but this stops less than 10% of the spam (as of December 2011), usually only stopping repeat senders, such as in cases where you're on someone's mailing list. Most spammers hide by changing their sending numbers. below are some ways to block mobile phone spam, also known as SMS spam or m-spam. They're not perfect, but they might hold you over until spam-blocking technology catches up with mobile phones.

Steps:
 
Blocking Steps

1. Block all text messages originating from the Internet. Since the majority of mobile phone spam is sent through the Internet (where spammers can text you for free) you can ask your service provider to prevent all Internet messages from reaching your phone. As of June 2008, this feature is offered by T-Mobile, AT&T and Verizon Wireless.
2. Create an alias. If there are some messages you want to receive from the Internet (airline schedules, hotel reservations, etc.), then some providers will allow you to create a unique alias, blocking all messages that are not addressed to your alias. This filters out spammers, who usually find their targets by sending text messages to random numbers (1234557890@txt.company.com). Give your alias address only to the people and website you actually want to receive messages from. As of June 2008, this feature is offered by AT&T, Verizon Wireless and T-Mobile.
   
   
   • Doing this may inadvertently block replies to your text messages. If the reply-to address isn't your alias and someone replies to your message or e-mail, their message will get blocked because it wasn't sent to your alias.
   • If your carrier allows you to block all text messages except when it comes from a specific address, you can create an e-mail account that has good spam filtering software and have your phone only receive messages from that specific e-mail address. Have people text message you at that address, and have all the e-mails from that account forward automatically to your phone.
3. Block a specific number, e-mail address, or website. Most providers offer this option, and it can be useful if the spammer consistently text messages you from the same number or e-mail address, or if they always include their URL in the messages they send. You can also block all (or the majority) of known phone spam numbers for your area according to a user-generated database.
4. Dispute your cell phone bill. If spammers continue to get through, you may be able to convince the carrier to drop the charges associated with those messages. You have a better chance at this if you call as soon as your receive the spam. 

Carrier Specific Blocking/Reporting Instructions

In addition to calling your carrier to add these settings, you may also be able to block spam through the carrier website as follows. (Keep in mind that the layout of the website may have changed since this writing, so feel free to update this page as needed.)

• AT&T:
• 1. First report your spam text messages. Do this by forwarding the message to short code 7726 (spells 'SPAM'). The system may ask you to report the phone number that spammed you.
• 2. Log in at http://mymessages.wireless.att.com. Under Preferences, look for the text-blocking and alias options. You can also block specific addresses and websites.
• Verizon Wireless: Head on over to http://www.verizonwireless.com, and make sure you're logged in first, if not, log in. Under "My Verizon" you should see "My Services", and then under My Services, you should see a list of options, at the bottom of the list should be "Spam Control". Go ahead and click that, and from there you can block up to five numbers and 15 internet emails/domains/etc.
• T-Mobile: Log into http://www.t-mobile.com and go to "My t-mobile" using the t-mobile sites drop down at the top of the page. Now, search for "Change plan or services" and click the link. You will be taken to a page with the section "Your Current Services" where you'll have to click the "change services" button. Here, you can block text messages, instant messages, photo messages, messages sent via e-mail, or even all text messages.
• Sprint: Log in at http://www.sprint.com. On the top navigation bar, move the mouse to hover over "Digital Lounge", then click "Messenging" on the smaller menu that appears. (Alternately, click on "My device & media" and then click on the "Messaging" icon.) Click on the "Block Texts" button under the "Texting" section. Select the "Block messages from all senders in my block list" option. In the text box, enter a phone number, email address or domain (such as Comcast.net) that you want to block. Click the "Add" button. Click the "Save changes" button.
• Virgin Mobile: Check the Messaging Settings page on Virgin Mobile’s website (http://www.virginmobile.com) to block text messages from up to ten telephone numbers or email addresses; you can also change preferences on your handset (VirginXL or VirginXtras > Messaging > Messaging Management).
  Source: www.wikihow.com