I recently made a credit card purchase at a Japanese shopping website. When I looked at my statement, the amount was in dollars (converted from Japanese yen). Later, I cancelled my order and was refunded the same amount in yen, but because of the exchange rate, the amount (in dollars) I was refunded (-$10) is less than the amount (in dollars) I spent ($12). Both transactions appear on my statement. Will my credit card company refund me the difference ($2) if I ask?
My opinion is not likely. You entered a transaction where you purchased yen with your dollars, then used the yen to purchase the items. Later, when canceling the order, the yen transaction purchased dollars. Foreign currency prices change constantly. The credit card company (bank) isn't responsible for the difference in price changes between currencies. If you were to cross the border to another country (say Mexico, Canada), attempt to purchase an item with USD, the vendor MAY accept your USD at a specific exchange rate for that day. Were you to re-visit the next day and return the item, a different exchange rate would be in effect and you would be refunded accordingly.