Some of our agents have gotten into hot water for lesser things, so you might have some recourse in this situation. No guarantees, but it might be worth looking into.
FWIW, I can likely see two scenarios that may have happened here. 1.) TA assumes you're the average flyer, and want a more affordable international fare (as most leisure travelers do, whether they book Y or J) and 2.) Airlines do not pay commission to agents; the only way for them to make money off of air bookings are adding a service fee, book through a vendor like Funjet (which pulls published and bulk fares) and Delta Vacations (pulls published fares), or in the case of expensive international fares they'll use a consolidator, compare the price to the published air, and add a markup that's more than the consolidator fare but still less than published airfare.