Sorry for necromancing this thread as someone brought it back to my attention on my list thread, and I realized I still mark it as "in progress", and I didn't make any follow up during my weekly sweep. I can see that OP has not been online for a while.

OP, suppose you read from guest mode, do you mind to update us if you followed others' very sound advice and got your refund by the bank? I think the procedure here is to inquire to the payment processor instead of the platform. In most cases, it's the payment processor's duty to handle the refund, not you or the vendor. For example, if you pay with your credit card in a restaurant or some store, and they double-deduct you, you're calling the bank and sit while you let them handle the matter, not inquiring the refund from the restaurant.

With Stake [the restaurant] confirmation that they didn't get the fund, it made things even more logical to pursue the payment processor. Kindly update us if you get this message.