Call Blocking

• Several cellphone providers in the U.S. allow you to block individual numbers from being dialed or from being able to call a specific cellphone. This feature is usually marketed as part of a parental control package through cellphone service providers. As of May 2011, these packages average $4.99 a month, on top of whatever your current cellphone plan costs are. If you're enrolled in such a plan, you can block individual numbers by logging in and entering them online.
  
  

Text Blocking

• You can also block text messages from individual troublesome numbers as a separate service. It's usually covered under the same parental controls plan as call blocking. This solution can be useful if your cellphone plan doesn't include a large number of text messages, and your dependents have a habit of going over the limit and running up extra charges. If you find it more useful, you may also be able to block all text messaging on a cell phone, or merely restrict text messaging to certain times of day. Talk to your cell phone service provider to find out what specific options are currently available to you.
  
  

Cell Phone Service Providers

• AT&T, Sprint, T-Mobile and Verizon are some of the U.S.-based cell phone service providers that offer you the ability to block phone numbers. Other providers may also offer this service -- in the U.S. and elsewhere in the world. The only way to be sure whether your company does is to consult its website, or call and ask if they offer such service.
  
  

Considerations

• Some cell phone service providers also offer you the ability to block international numbers, purchases of downloadable content, and even calls to directory assistance numbers like 411. You can also restrict Internet usage by amount, time frame of use and content. Allowed or trusted phone numbers can also be set on cell phones in use under these types of service plan, though specifics will vary from provider to provider. Some providers restrict the number of phone numbers that you can block at one time; for example, AT&T only allows you to block 30 numbers at a time.