It’s kinda obvious, isn’t it. Just recreate the community/magazine on lemmy/kbin :D

Maybe advertise your community in the subreddit while telling everyone that you have been replaced as a moderator.

They came after a small sub I moderate today too. My response was to make a sticky post to the sub with the contents of the mod mail and a recommendation for everyone to move to kbin or lemmy. I hadn’t planned on giving reddit any more free content anyways given their behaviour.