If they want to continue this (which I'd argue is a bad idea given they've presumably been discovered), the way to do so is to operate entirely in the underground (using Tor or other anonymization systems) and host any required infrastructure in a country that doesn't care - Russia comes to mind, even more so given the recent events.
The mere fact that they received a C&D and it had leverage over them already suggests a massive failure. Why was there a place to send a C&D to begin with? The proper legal department contact for such a project is /dev/null, so something failed big time if that C&D found its way somewhere else.