Ok for PACD & DRYS, looks like you didn't get rid of the stocks fast enough before it got trade-halted, unfortunately although it's so strange. They shouldn't halt the trading for no reason at all.
But for the first case, if your limit order WAS indeed filled and you have the proof that you got filled, your broker shouldn't be able to turn around and reverse the trade. They have no right to do so unless they can prove that your trade was made in fraud that somehow you manipulated their system to get the order filled or etc. They cannot reverse your trade based on their mistake; it's their mistake and that's too bad. Just like if you had done a market order that you actually didn't want to they wouldn't allow you to go back to them and demand them to reverse the trade. If you wouldn't be allowed reversal of trades in similar situation WHY should they be allowed to do so? It's them who filled your order, a completed transaction is a done deal and they are not entitled to any "cool-off period" which is only available to consumers. If any time when you do a trade and profit they can just reverse the trades on you then what's the point of trading? I would suggest you to contact the financial regulatory body regarding this. For them to reverse a trade on you for you to losing $3 million is not right.
This is very strange. You always seem to have very strange things happening to you. First you got scammed by Nanko Trading now these three cases.
Good luck!