I'm sorry to hear your experience. I have only dealt with QF directly and they were quite good and open to discussion as to what the rules were; it seems you were less lucky and seem to have been unfairly treated.
QF is overwhelmed with a large volume of transactions (combination of Ansett going out of business and changes in the QF frequent flyer plan). Also they may treat travel agents on commission differently than when they are dealing with the public. Did you ever speak to QF directly, or was it only through the travel agent? I can't blame the TA for going with QF to get the commission, but in the US the AA desk is the best choice. If it makes you feel better (or worse) I did have a complicated reroute with QF in Melbourne, so they can manage at times. The real problem is that Oneworld needs more integration before it functions as it should.