1. Go to this user profile page.
2. Tap on the menu icon on the top left corner of the screen.

OR Go to your Profile settings page and click on Edit Profile on the bottom right corner of your cover image.

2. Click on Blocked Users.

3. find the User you want to unblock and click Unblock. 

For Android: 

1. Go to this user profile page.
2. Tap on the menu icon on the top left corner of the screen.
3. Tap on Block User at the bottom of the screen. 

4. Select "Yes" to confirm user block. 

To Unblock user:

1. Tap on Profile icon item on left upper corner.

 
2. Tap on Settings menu item.

3. Tap on Blocked users.

3. In blocked users window screen, Choose "UnBlock" to unblock the selected user.

For iOS:

1. Go to this user profile page.
2. Tap on the menu icon  on the top right of the screen.

3. Tap on Block User.

4. Tap on "Ok" to confirm user block.

To Unblock user:  

1. Tap on Profile icon item on left upper corner.

 
2. Tap on Settings menu item.

3. Tap on Blocked users.