I am using IB and have had this happen 3 times so far. I put in an order for a nasdaq stock and the order does not show a fill but it does not allow a cancel . So I call IB and am told they must call the exchange to find out but it may take up to 2 weeks to find out if I am filled or the order was lost.( excuse me but what do I do in the meantime?) So the person offers to call me today to let me know what the exchange ( most times its supersoes)says. Most times the IB person never calls back. After a day the hanging order goes away and I keep checking my positions. So far I am lucky in that these orders were never filled but I don't want to assume they will not be. Is there any effective way to deal with this?