Paypal you gives you 45 days to file an item not received dispute. After that, you may be able to file a chargeback if paypal was funded with a credit card and if you haven't exceeded the chargeback deadline which may be 90 days from end of sale.
I don't know what Canada Post offers but if they have a mail fraud division, you might want to pursue a mail fraud claim as a last resort.
Non paying buyers deserve unpaid item strikes.
