The same Do Not Call service you may have used to prevent telemarketers from calling your home phone, is also available for your cell phones.
Telemarketers calling your cell phone will cost you because you'll be charged for the air time during the call. You can prevent that from happening in two ways.
You can call the following number from your cell phone and subscribe to the service: 888-382-1222. Follow the prompts to register. You must call from the same phone you want blocked.
You may also use the blocking service on the government's Web site at https://www.donotcall.gov. You can register multiple phone numbers on the site.
According to the Web site, "Scammers have been making phone calls claiming to represent the National Do Not Call Registry. The calls claim to provide an
opportunity to sign up for the Registry. These calls are not coming from the Registry or the Federal Trade Commission, and you should not respond to these calls. Your registration will not expire. Telephone numbers placed on the National Do Not Call Registry will remain on it permanently due to the Do-Not-Call Improvement Act of 2007, which became law in February 2008. Read more about it at http://www.ftc.gov/opa/2008/04/dncfyi.shtm
In addition, the Web site advises, "The National Do Not Call Registry gives you a choice about whether to receive telemarketing calls at home. Most telemarketers should not call your number once it has been on the registry for 31 days. If they do, you can file a complaint on the Website. You can register your home or mobile phone for free."