As long as USD isn't shown on the order page, invoice, or receipt, I agree 100%.
It wouldn't matter if a page showed USD prices along with BTC. Paying in BTC implies being refunded the full/original BTC amount, no matter what USD prices are on the page. Anything else is a seller hedging value against the buyer.
by the same reasoning you can buy 1oz now, then come back 5 weeks later and say "BTC has doubled, send me another 1oz, ok"
not.
No. Read this person's issue again. He didn't receive a product. The product wasn't even sent.
He
can't come back weeks later and expect a refund in anything other than the original amount of BTC he paid. Likewise, he
can't expect more than the original amount of metal he purchased, as you highlight. The comparative rate of BTC is meaningless. If Coinabul can't provide the product in a timely manner, then they can't. That means the refund is in BTC. It doesn't matter if BTC crashes to $1 USD: 1 BTC either. Refunding in a different BTC amount is inexcusable. Doing otherwise is laughably unfair. I'm surprised by anyone who doesn't realize that.