Refund policies are contractual terms, so whatever is agreed to is the right answer.

I think a twist on your question, where we're talking about breached contracts, is more interesting. If you pay for a service that never gets rendered and the company is ordered to pay you back and this wasn't explicitly covered in the initial contract, what are you owed back?

In this case, I would generally agree that they should return whatever you paid with, because that's the transaction that became voided.

It would open a huge can of worms if they could payback with their own selection of media of exchange.