On Thursday, May 20th, the TSX cancelled part of some open orders while executing another part of the same order (the odd-lot portion).
This affected some Questrade clients with open orders. If you notice that you had an open order that was partially executed and partially cancelled by the TSX, you can enter the cancelled portion as a new order.
If you have any questions please contact Questrade client services at 1.888.783.7866, or www.questrade.com/livehelp.