Originally Posted by ijgordon

This comes up quite frequently. AA.com is notoriously bad at telling you what you're purchasing. It seems they are getting a little better though, as they're specifying "full refund to original form of payment." Normally you'd have to look in the detailed fare rules and decipher a bunch of unformatted text to determine the refund rules, and as you allude to, the full fare rules are well-hidden during the purchase process. (It's not until just before making payment (or putting on hold) where the box to "accept the terms" has a link to the rules in small print.

My suggestion - first see if you can get the full fare rules, if you know the fare basis code, it is usually possible to pull up the historical fare rules as of the date of purchase on ExpertFlyer.com.
Beyond that, if you have the screenshot of "full refund", I would file a complaint with the Dept. of Transportation, which will ensure AA has someone with half a brain to respond. You can also attempt a chargeback with your credit card/bank, but the bar for successful chargebacks with airlines is high.
A last resort would be to file a small claims case against AA. But if the fare rules specify a partial refund, your chances of winning are much lower.