If seller cancelled due to him not understanding how things work, a refund is automatically made, BUT refunds go back to source, and in case of paying by credit card can tske up to 30 days.
In this case however, your payment to seller is still held, so cannot be used to refund, and money should be taken by ebay from his bank account and refunded to you. Any delay is basically down to seller not honouring the sale, as that is the best way to get money released.
In due course leave negative feedback, just say “seller would not honour the sale”.