It probably is not a "tracking" number, but a Delivery Confirmation number.
For the buyer, it has no purpose except to reassure you that the seller has paid for postage and probably mailed your item.
You can enter it on canadapost.ca and if the parcel is in Canada it may show up. Or not. It will show up when the parcel has been delivered, at which point you don't need it.
Some Canada Post services use the number for postal insurance. Some use it only as a record of payment of postage.
Cheap postage does not necessarily mean slow postage. Letter/Light Packet is relatively cheap, but is an Air Mail service. Small Packet Air is also pretty fast.
China Post heavily subsidizes international mailing, so if a Chinese seller uses fast Air Mail shipping, it may be both faster and cheaper than a domestic service like Regular Parcel.
If your parcel has not been delivered 30 days after your payment, contact the seller and ask for the Delivery Confirmation number and date of shipping. (He may not have the former, which is not really a problem. The purpose of asking for the number is to push him into response). If the parcel has not arrived 43 days after payment, go to Paypal and start an Item Not Recieved dispute. Do not close it, no matter what the seller says, until you have either your money or the item.
