You have only 45 days (to the minute) to start a Paypal dispute after the auction ends.
If you still have a few hours, do it now.
To get a refund through Paypal, you will be required to return the items you did receive with Delivery Confirmation. Within North America this is Expedited Parcel, which is found on the Canada Post website under "Business".
If 45 days have passed, go to the credit card as sciguy suggests and ask about a chargeback. The 1-800 number is on the back of your card.
Whether you get a refund or not, you can leave feedback for up to 60 days. You can Respond to feedback, yours or the sellers, indefinitely. The most effective feedback or response is calm and factual.