Article: You can also search for "Smart Limits for Wireless" in the search bar at att.com. It is free for 90 days, then it is $4.99 per month per mobile phone on the account. You will need to have the right login and the rights to make changes on the account to order Smart Limits. You can also go to an AT&T Wireless store with a copy of your latest bill or call the AT&T customer service number with your account number.   Specify any more information as prompted until the transaction is complete. Type in up to 30 numbers to block from calling or texting your phone. You can also use other features with Smart Limits, such as controlling Internet browsing time, the number of texts the phone can use and limiting purchases from the account.

What is a summary?
Go to http://www.att.net/smartcontrols-SmartLimitsForWireless. Click the "Order Now" button on the right side of the page. Login to your AT&T Wireless Account when prompted. Find the mobile phone that needs numbers to be blocked. Click on the "Wireless" tab, if you are not prompted to the screen to order Smart Limits on your phone. Select the phone that you want Smart Limits to be added to. Manage Smart Limits under your Wireless account.