Screen shuts down and no restart during phonecall

Hello! I have problems with my phone during phonecalls. The screen shuts down when I start a new phonecall. Sometimes even without me putting it to my ear. When I want to shut down the phonecall the screen is dead. It´s a big problem when nobody answers. To stop a long voicemail I have to rip the battery. Is it possible to do something about this?

This issue is already discussed here:

Please read the workarounds provided in the first post and if they don’t help continue in that topic.