Could Amazon gift cards be added as a payment method? The seller of BTC would just need to provide an email address (which doesn’t need to be tied to an Amazon account). The BTC buyer would buy an eGift card from Amazon for any amount which would be sent to the seller via email, and the seller can then apply the voucher to his Amazon account. (It wouldn’t need to be spend straight away, and can sit as a balance for up to 10 years).
As far I can can tell, it is not reversible, and since if the voucher is sent by email directly from Amazon, the buyer wouldn’t see the code, so no chance of sending an expired voucher