Unless the exchange rate changed dramatically between the purchase and the reversal, you're still going to be out a little bit because the bank charges a fee for foreign currency conversions. The exchange rate on the purchase is about 2.5% higher than the "posted" USD-CAD rate, while the exchange rate on the return is about 2.5% lower than the posted rate. (Same as buying and returning items at a store when shopping in another country.) That's out of AC's hands: you'll have to take it up with your bank if you want that difference reversed. Good luck.