Don't use Surface. It will not arrive within the period Paypal allows for Confirmation of Delivery.
Ignore anything else the seller tells you. He is blowing smoke. The important standards are set by Paypal.
Frankly, I would stop talking to the seller. He seems to be messing you about. Open the Paypal dispute immediately.
Remember that if PP does not find in your favour and refund you, you can also go to the credit card you used to back the PP payment. (PP is just a mediator.) While cc deadines for chargebacks are longer, they also want to see that you have returned the unwanted item. Some will accept Proof of Shipping, but not all.
Oh, and Surface is NOT 30 days. It is more like two to three months. Canada Post is an optimistic organization.