I am really upset. This is the second day in a row this happened. (First report: http://www.elitetrader.com/vb/newreply.php?action=newreply&threadid=83006). Two days ago, we cancelled an order AFTER the close, and the order went through the next day at the opening of yesterday. Yesterday, cancelled an order one minute BEFORE the close and the order went through today. No trace of either of the cancellations in the IB system, which might give an inkling as to where to find the problem. Since the order was placed as GTC, the IB system redsubmited the order after midnight, at the start of next day. Today, cancelled an order AFTER the close and it stayed as a pending request for cancellation for about 20 minutes before the order disappeared. The IB rep says that happens with cancellations at the close, but he believes it would not have been left as an open order for the next day, because in this case he saw the cancellation request. Ultimately it did cancel today. In spite of the low rates and the high interest for credit balances and ease of use of the system, problems occur with the system, and the customer is not believed.