I'm having the same issue. I purchased tickets with an AA phone agent. I canceled 5 hours later, months before the flight date. No refund.

Phone agents gave conflicting explanations. Refund request form online said no refund. BBB complaint brought a response from customer relations explaining that it was not a new booking but a rebooking and so not eligible for a refund under the 24 hour policy.

It seemed like a new booking to me. I booked a new flight, and just gave them the flight credit info when they asked how I wanted to pay for it. About $1000 was flight credits and $4500 cash.

Anybody have experience with this?