Basically what you were told was correct. You have a direct flight with 1 coupon. If you were to checkin in YYZ, you would get a boarding pass and a reboarding pass. An agent cannot just create a coupon so one can fly sb.

If an agent were to get around this, it would create a ppbm issue. BTW, are you checking bags? If so, for your benefit, stick with what you have.