Here's a question for you though. If the btc price had dropped to below the btc price you paid when ordering, would you still want the refund in bitcoin? Or do you just want whatever will give you the most value?
Here is your answer, If you paid for your $12k Neptune with $12k worth of BTC, then you will get $12k worth of BTC back.
Ask someone who paid in BTC and asked for a refund what happened.