Return labels are confusing as there is no way on ebay.ca to do them automatically.
If you clicked refund upon return eBay shouldn't have refunded him until after you got the item back. Once the buyer opened a return you had 3 days to provide him with a label. Did that time go by and the buyer escalated the case? Or did you click on refund (which means refund right now and no return required) by mistake? If the buyer escalated the claim then ebay would refund from your funds and you would also get a defect for unresolved claim.
Either way, the buyer is not obligated to send you back the item if they have already been refunded. But many buyers are honest and will still send you the item back. If the buyer is in Canada, you could sign up for Canada Post small business so that you could use their online website to print a label and get a small discount. You could also buy a Canadian return label at the post office.
If the buyer is in the US you would have to print a usps label through an online company such as Pirateship or Shippo. US buyers can't use Canada Post labels so it is more complicated to send them a label.
Once you have the label you can save it as a .pdf and send it to the buyer through the return or you can ask them for their email and then email it to them.