Regarding your situation and concerns of other comments...
Many people in this thread point out that marketing and creating an audience is difficult work. But I think obvious-in-hindsight solution is to always keep a backup of your own content no matter what platform you publish it on. I'm not sure how Medium interprets their rules exactly but I would be suprised if you couldn't at least link every post back to a mirror on your own blog which would let you both generate an audience and prevents you from loosing everything is medium goes nuclear on you.
As always, back up any content that you care about. Don't just backup your own content but also that of others - ever relize a youtube video you like has been taken down by a bogus DMCA claim?. Online services may have their own redundency but that doesn't matter if they decide to delete (your) content.