Web Trader Cancels Stop Orders at Execution

Each time my Stop Limit Order gets triggered, instead of actually entering the market, it just gives me a notification saying "Order successfully been deleted". WTF!

This has costed me so much money in the last two weeks, but has been happening for much longer and I didn't realise. If you don't catch the notification that disappears in like 3 seconds, there is no way of telling what happened to the order. It just completely disappears. I could never figure out what was happening, but now I know it happens on Stop Limit Orders through the web, and it seems to be every time.

What is happening. Furious that this bug has costed me so much money. There is no way to tell if the order is going to fail, because it fails AT execution, and by the time I notice price is gone without me because of the way i trade.

Help would be appreciated.