Considering that:
- The buyer is willing to receive the Krugerrand he bought,
- It may get Coinabul into trouble, to send Gold to a country where it is not allowed to do so, and
- 2weiX is willing to ship the coin to the buyer, and Coinabul can easily pay him the market price of the said coin,
I believe that this is a reasonable way to make all parties happy.
How is Coinabul supposed to trust 2weiX to ship the goods? What happens if that package is "lost" - who pays for it?
No, the best way to make all parties happy is for Coinabul to refund the full amount
in USD equivalent as their policy states. Including shipping (why they didn't include shipping as part of the refund to begin with is beyond me). The customer can then take his business directly to 2weiX and deal with him without having Coinabul as a middleman.
Hm, undecided

Upon lock-in, the seller transferred the ownership of a Krugerrand to the buyer and undertook a commitment to deliver it to the buyer. The buyer could not reasonably have been aware that the seller cannot deliver to his country, as importing is not forbidden, and the country was available in the seller's list. As seller is canceling the deal because of his own fault to deliver, he needs to make sure the customer is not worse off than he would have been, if the seller had delivered.
Even if seller's terms say something, they may not be used to defraud a buyer who has not committed a fault. Especially as it only costs them about $100 (or nothing, depending on if and when they transferred the Krugerrand back to themselves).
I got a reply from Coinabul regarding the other one, and it was very courteous and on top of the situation. I am sure they understand how to deal with this one also.