If you sent Xpress Post, there should be a signature on file taken by Canada Post.
I normally ship Expedited Service no signature with insurance coverage.
We have had two items apparently not received by the recipients over the years we have been selling (Actually a pretty good record by Canada Post I think).
In one case Canada Post said the goods were delivered, but they could not prove they had actually got to the recipient (as their parcel scanning is as accurate and consistent as the weather forecast in North Bay in May!!!!).
The claims clerk told me I should have sent the goods requiring a signature and I told her that insurance and the requirement of a signature are two different requirements and one is not required to have the other as Canada Post does not mandate that you select the signature option and charges for it over and above. Finally I was reimbursed wholesale value and cost of freight.
The second one was goods shipped to the US (actually an APO address, so who know where in the world the goods were really destined), that were never received. Again although it took some time, as CP had to contact the customer to verify they never in fact did receive the goods, I was refunded.
To proceed and process the claim you will have to provide them with the invoice from your supplier showing the value you paid for the goods. Remember you will only be reimbursed wholesale value. You will probably also have to provide contact information about the recipient and Canada Post will contact them to verify goods not received.
Contact the Canada Post Claims Department and file a claim. (And remind the clerk that a) it is not their money they are refunding and b) you paid for coverage in case of none-delivery, they didn't deliver so either return the goods or pay you out.....) Oh ya, be prepared to spend some time on the phone as their claims system is somewhat antiquated.
Jeff