Currency Exchange Orders Completing Eearly

I put in an order to convert 5 divine orbs in exalted orbs. The cost for this trade is 250k gold. I execute the trade, and it sells 1 divine orb and then displays "order completed" I get 1 divine orbs worth of exalted instead of 5 and have just lost 200k gold for NOTHING. Stop cancelling orders! I want my order to stay up until it is filled. period. no exceptions.