How to block a number on the iPhone 4s for AT&T?

This is like URGENT.

Like i said, my carrier is AT&T and i have the iPhone 4s. I would like to block a number from texting me and calling me continuously. Without jailbreaking my phone, someone please help a sister out with blocking this person's number. I recently read that there's a way for verizon customers to do so. If that's the case, then i think its only fair that AT&T has SOME WAY. Please Help A SISTA OUT! PROVIDE DETAILED AND ACCURATE INFORMATION THAT ACTUALLY WORKS! I CAN'T STRESS THAT ENOUGH! Please RESPOND BACK A S A P!

AT&T has a blocking feature, you can activate 0n the Internet with your account… It is called 'Smart Limits'… You can block 15 numbers, and has other nice features… (Or you can call AT&T Cellular to activate.) You just go to the Smart Limits site on the AT&T, and enter the numbers to block… You can view the site at: https://www.smartlimitsforwireless.com/slsc/GoBlock.do?msisdn=18188881824 It is not free, about $4.99 a month… There's an app. Also for blocking Iphone phones, but you have to jailbreak it first!