So sorry this is happening to you, Mike. I am a recent follower of yours and have already had 2 responses from the fake account. The first one vaguely puzzled me (so I ignored it), but I recognised the 2nd for what it was and reported it. I then checked for a genuine post of yours thinking I might put a PM on it to let you know. But I found this and clearly you know only too well. I sincerely hope that the Medium team find a way to stop this rot before it endangers the whole platform.