Was the seller refunding you?
Or are you the seller?
If you are the seller and the buyer backs her PP account with a bank account, she wrote you an e-cheque. While the money is already out of her bank, it is still being processed through the US and the CDN banking systems. This can take up to 10 business days.
Until then, you cannot print a shipping label through PP.
Since you are a new seller, your payment will be Held by PP against your good performance for 21 days after clearance. You still have to ship. And it is safe to do so.
PP will release enough of the payment to pay for a PP shipping label.
Not only is the ability to print that label a useful indication that the payment is cleared, but for some Canada Post services PP gives a 5% to 18% discount off PO counter prices.