Trading on a platform requires you knowing their terms and conditions for which I believe you signed up for and another, the platform have the right to revoke or put pending whatever they deem fit to do at anytime and any day they fill like doing it.  Locking of account might sometimes likely have to do with suspicious activity being noticed from a particular user or customer account on board that platform. Either way, sometimes when  the account holder might be called upon for clarity, his details must be inline with what he has presented before upon being registered with the platform. In your case I have no clue as most evidence here in still not clear but I think their own side of the story needs to be heard as well for proper assessment  and possible solution. If they have a representative here feel free to tag them or mention the user name so as to facilitate the whole process.