Just flag him on any board he turns up on. If you look at Ria20 posts they are the same on any board he turns up on! The person whoever (Ria20) are, they are a parasite!
There does seem a lot less trading over quite a few of my shares. But it does seem when a share is not getting interest there are claims of it being held back. At least we seem to be not being visited by the pump and dump crews!
I would save your breath on pursuing an investigation. Nothing will happen as the big boys have done this for years and blind eyes will already be shut.