The OP's specific case has been pretty well covered here, so I won't re-hash that.

I will, however, second the OP's request that the CO reps get properly trained so that they could explain the situation to the OP instead of FTers having to do it.

Why do we know it better than they do? Because we have to live with it. Perhaps CO should have a three day training seminar for their reps someplace boring or with lame weather (summer in Midland, perhaps) for which the reps are provided a certain amount of money for travel and are allowed to keep whatever's left, giving them an opportunity to experience booking a flight. Then the seminar should wrap up early at the end of day two, leaving the agents figuring out how to change flights to go home early while not spending too much more money.