Welcome to Nokia discussions board!
You can in fact reinstall an update that you have installed on your device. Just connect your phone to Nokia Suite on your PC and go to software updates and "reinstall".
If the issue persists, please reset your device. First of all back up all contents: Options > Back up on Nokia Suite. Then type *#7370# on your phone's keypad. When prompted, enter lock code 12345 which is by default, or the code you have changed it to. You will then be able to access social apps and Nokia Store again.
Let us know how you get on and feel free to post any other questions you may have.