I am using Ubuntu 12.04. I use Empathy as my default messenger. I had blocked someone in Empathy but now I want to unblock him. The person whom I blocked is using Gmail.
Open the Contacts window (empaty itself).
In the application menu you have Edit-Blocked contacts.
There is the list of blocked contacts. Select one and click on minus button below the list.
Open the Contacts window (empaty itself). In the application menu you have Edit-Blocked contacts. There is the list of blocked contacts. Select one and click on minus button below the list.