In Instagram, you can make someone who was already your follower unfollow you. You only require to block your follower and this ensures that the person cannot look out for your Instagram account or view your photos. To block, open your Instagram account page and open the user's page, who you wish to bock. Tap the button in the top right corner of the screen. You will see numerous options. Click the one saying "Block User". Check out http://help.instagram.com/customer/portal/articles/495190-how-to-make-someone-unfollow-you.