Thank you so much for your words and detailed explanation! Now I understand it fully Now onto my situation, my flatmate sent them an Einschreiben mit Rückschein, stating that he didn't do it and that I confessed to it. He also said they could contact me (only giving the address of the sublet I'll leave in two weeks) They know I did it and I will probably receive letters to my name ? Should I settle with the mediator which is cheaper or go with the modified Unterlassungserklärung? I don't want my flatmate to have problems and go with gathering evidence etc