Hi @НиколайС, sorry to hear about this.
As there is no setting available in the phone enabling you to add or remove the fingerprint manager from the settings, I suggest that you try to repair the software using a computer and Xperia Companion. Keep in mind though that a software repair will erase all user data from the phone, so make sure to do a backup of your user data before the repair.
If the fingerprint manager still does not appear after the software repair, I am afraid that the only thing left to do is to get in contact with your local support team in order to have your phone sent to an authorized service center to be examined and possibly repaired. If you have any questions regarding the service such as routines, warranty and consumer laws, these kind of questions are best answered by your local support team as well.
I hope that helped!
