Hi @GarciaMarc, sorry to hear about this.
Do you have any type of screen protector or a protective film mounted on the display of your phone that may affect the behaviour of the touchscreen/display? Also, have you been able to carry out a quick test of the touchscreen in order to see if it works as intended? To do this, find and tap Settings > Support > Xperia Tests > Touchscreen.
Another thing you can try is to reboot your phone in safe mode to see if the touchscreen behaves the same way there. All apps downloaded from Play store is temporarily deactivated while in safe mode and by doing this, you can see if this behaviour is caused by a downloaded app. For more information on safe mode and how to use it, click here.
If the behaviour of the touchscreen persists in safe mode, I would suggest that you try to repair the software on the phone using Xperia companion and a computer. Keep in mind though this will erase all user data from the phone, so make sure to do a backup before the repair to prevent data loss.
If none of these measures manages to improve the functionality of the touchscreen, My suggestion is to get in contact with your local support team in order to have the phone examined and repaired by an authorized service center. If you have any questions regarding the service such as service routines, warranty and consumer laws, these kind of questions are best answered by your local support team as well, as they vary between markets.
Try these measures and feel free to keep me posted with the results!
