The most common way to view your block list is through the dialer settings. Open the Phone app from your home screen or apps drawer.
Once you have found the blocked list, unblocking is simple:
Call and text messages blocking issues with Galaxy phone - Samsung
To quickly recap, simply open your Phone App > Three Dots > Settings > Block numbers to view and manage your list.
No. When a blocked number calls you, they will usually hear one ring before being sent to voicemail. They are not notified that they have been blocked.