I have a basic economy ticket I bought yesterday partially with flight credits and partially with cash for a flight taking off tomorrow. When I talk to AA customer service they say I am still within the 24 hour window for refund but if I cancel, it may take up to 20 days to get the flight credits back to re-use again.
They seem confused though and I'm wondering if they're giving me bad info.

I want to cancel and immediately rebook for a different flight tomorrow, using the flight credits. In your experience, how long does it take to get flight credits back for re-use when you cancel? Does it happen immediately, or does it really take weeks and weeks?