Think youd have to ask your service company to do that for you..cant personally do it I dont beleive
You will need to speak with your cell phone provider. It will most likely *ONLY* block phone calls so if you are getting text messages as well from an unwanted number, you need to check with them to see if there is anything you can add (it will most likely cost money) to block those as well. I know Verizon and Sprint have products like this.Net10 cell phone service how to block a persons number
this facility is enabled for you only if you contact the cell phone service provider.
call the company customer toll free number and ask to block the particular number.What happens if I block someones cell phone number from my aim ?