*67(area code) and phone number
ONLY WORKS ON A CALL
You'll have to call AT&T to ask them because every phone provider is different, there may or may not be a cost to block the number.
1-800-331-0500 or 611 from your wireless phone
um im not sure. I think you call at & t and they block it but I think it costs money..I HAVE NO CLUE. I have verizion thoocan you block a phone number?