Originally Posted by
xliioper
Airlines started incorporating USD $10 DR tourism tax into ticket fares starting in 2018 (it used to be payable on arrival at airport). You can see it when you do a tax breakdown of ticket price. Perhaps AA is not refunding this tax for some reason (maybe related to the fact that it didn't used to be incorporated in tickets). Currency conversion changes shouldn't come into play on US purchased fares as I believe all DR taxes and fees are charged in US dollars.
This is what is happening. To get a refund, the OP must file with the DR government. I am not clear if that's still an available option for everyone or only limited to residents/citizens; the rules have changed several times in the last few years.