Are you a German resident or otherwise subject to their jurisdiction? What would happen if you just ignored the lawsuit, and/or ignored the final judgment?
Eventually they'll sue you for damages, the court will rule that you have to stop what you are doing (as they already did so, and violating a court order seems like a surefire way to escalate the situation), plus the monetary compensation for the damages. And at that point it's just easy-peasy call the collections agency, and they'll just make your life more and more miserable by taking your stuff/car/home/etc. (Similarly if "you are" a company.)