How did you buy a product on Amazon with Bitpay? Did you buy Amazon Gift card from their Bitpay apps or you just directly use their Debit card?
Because if you bought Amazon gift card from their apps and redeem already in Amazon it is not refundable or you can't charge them back.
However, if you directly buy in Amazon with the debit card they should give you a refund.
Look at this terms under "8.3.4 Refund Reserve".
https://bitpay.com/about/termsHave you tried contacting them directly to their phone number 1-855-884-7568 ? and maybe they can assist you more than the email support.