RE:What are the laws regarding orders being cancelled..If in fact they do cancel the trade (which they have the right to do under certain circumstances - https://thecse.com/en/support/dealers/trade-cancellation-and-correction-policy), what it means is that the trade wasn't supposed to be accepted in the first place basically.
So, if for some reason your broker/platform was able to make a trade on your behalf when they shouldn't have been, it's NOT considered a valid trade to begin with.
Sucks for anyone impacted, but I would wait and see how this plays out (and wait for formal confirmation) before fully panicking...