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Facebook removed all intergration with Android if I remember correctly, Sony has no control over this and it is classed as a third party application.
I recommend you reset the app by going to Settings > Apps > All > Facebook > Clear Data > Force Stop, then restart your phone.
Otherwise, download the latest version of the facebook app from the Google Play Store.
If you are still experiencing issues, you will have to contact facebook support for the reasons stated above.
Restarting the phone dumps the temporary memory, which is likely why it resolved the issue. If you do experience a similar issue in the future please do try resetting the app as I mentioned above.