You only get one opportunity to claim a refund on eBay, so as you cancelled it you have unfortunately thrown away your right to a refund.

For future reference, you can open a case when an item is overdue for delivery. You are assured of a refund unless the seller can provide racking proof of delivery. Provided you don't cancel it!

How did you pay? Your best hope now is that your payment provider e.g. credit or debit card issuer may be able to help.