Hi @Aleksei31, I am sorry to hear about this.
Your question has been translated to English as this is an International forum, please post any replies in English and it will be easier for me and other users to assist you.
If I understand you correctly, you are from time to time unable to swipe down on the screen in order to see your notifications, am I right? Have you been able to carry out a quick test on the touchscreen in order to see whether the top part of the display is responding? In order to do this, find and tap Settings > Support > Xperia tests > Touchscreen.
Another thing that you can try is to reboot your phone in safe mode in order to see if the unwanted behaviour persists there. All apps that you have downloaded from Play Store is temporarily deactivated while in safe mode and by doing so, you can see whether this behaviour is caused by a downloaded app. For more information on safe mode and how to use it, click here.
Try these measures and let me know how it goes, and feel free to correct me if I have misinterpreted your question in any way! 
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