I think this should be a clear-cut case for you. I mean you selected the option that says "full refund to original form of payment" and AA doesn't want to give you that. That text is pretty unambiguous IMO.

FWIW I tried to book a similar ticket today, which as you indicated says "partial refund..." but when I clicked on the "detailed fare rules" link at the end, I get a completely blank screen. So not only are there no detailed fare rules accessible, I would have no idea what "partial refund" means.