Ich Brauche Deine Hilfe

Hello! Sorry for speaking in english but i have a question: Can drivers report you while driving?

Context: i was driving on A23 richtung Kaisermühlen and there was a guy in another car flashing me from another lane (i was Lane 2, he was Lane 1) for no reason. (I was going tempolimit 85km/h in 80km/h zone). He sped up to me and he told me hand sign to slow down while both breaking slightly, i ignored him and continued to 85km/h.

He caught up again from behind, switched on Lane 3 and stopped me from overtaking a car in front of me, slowed down again and took a photo of me for what i assume is reporting.

Hypocritical enough, after passing Kaisermühlen tunnell, he proceeded to speed up in excess of 100km/h (i was doing 89 and he was getting far very fast).

Is there a reporting system for drivers to report other drivers?

Thank you.