-Product was paid for with BTC.
It's like me complaining that I paid in GBP and got back less GBP because the US dollar got weaker.
1. If you were quoted a price in GBP, you have the right to get same amount GBP in case of a refund.
2. How many websites have you seen pricing their products ONLY in USD and informing their customers that they accept payments in GBP as well? I know how many. ZERO!
3. If my credit card account is run in GBP and I want to purchase a product priced in USD, the credit card processing company is contacting the credit card issuer to make the currency conversion and TRANSFER on my behalf USD! If I'm paying with bitcoins what I TRASFER is bitcoins, not USD! The refund is nothing else than the reversal of a transfer! The original transfer and the reversal of the transfer must be in the same currency and in the same amount. This is why it is called refund! If I pay with bitcoins the currency of the TRANSFER is bitcoins!