How do I unblock a number on ny Samsung galaxy s 3

Go to contacts and then to the contact that you want to unblock. when that contact is opened on the screen go to top right/left corner and press a 3 dots symbol and then select unblock contact.

Are you talking about facebook messenger? did you log in?

This is for S5.. should be similar:
Block And Unblock Calls From Number On Samsung Galaxy S5
or try here:
The Cell Guide

If you're using hangouts to text and want to unblock the number you first have to unarchived the conversation to see the number in your list, from there you can unblock

The only way to unblock it is to take it to get unlocked.

Do you want to break network lock code from your Samsung galaxy s3 ??? Did you misspell the work unlock as "unblock" ? If so, use unlock code to unlock your Samsung Galaxy s3 from carrier lock . You can get code from any of the online vendors like Mobile-Unlocker.com to unlock it
OR
If you want to unblock your Samsung Galaxy s3 , contact your network provider and get your mobile fixed .

ouch same prob search www.google.com

http://www.youtube.com/watch?v=vxC1wzPXOQ8

glad im not the only one i have the same problem with mine but it just seems to be o2 numbers, i have taken it back to the shop, and they i have changed the sim card about 3 times and they sent it off to samsung and they apperantly changed the handset and i still am having the same problem, they are now saying it is a fault with samsung and they are working to get a new softwear to solve it, so we just got to wait!!