No. Unfortunately, unblocking a number does not retrieve text messages or voicemails that were sent while the block was active. Those messages are lost unless the sender sends them again.
Would you like a wireframe sketch or user story for this feature? att unblock number
Usually, no. The change takes effect immediately. However, if you are having trouble receiving calls immediately after unblocking, a quick restart of your phone can help refresh the network connection. att unblock number
Most users block numbers directly through their device settings (iPhone or Android). AT&T respects these settings, so you must unblock the number through your phone first. att unblock number