I had the exact same thing happen a few months ago Parrot provided letter that drone was defective and told me to contact Amazon in USA for replacement
When I reached out to Amazon they did not have a clue - but while I was on phone with them I provided the confirmation letter
Then at same time I had them call Parrot support while I was on hold - Parrot confirmed
Amazon agreed to refund cost of purchase - but when I received amazons confirmation it was only 80% of purchase price - 20% deduction for restocking fee
So i got back on the phone with amazon and pushed back - got a hold of a supervisor and they agreed to give me an amazon credit for an additional 10%
It all worked out ok in my case as I was able to purchase new drone that was on sale, but took some effort