Open Question: is there any way canada post can find an invoice with a receipt?

I shipped via express post, and the girl never gave me the tracking number that comes off the actual prepaid envelope, all i got was my debit receipt and the item receipt. I'm wondering if i can take them in there as it was only a couple days ago, and they can use the barcode or some number on the receipt to look up the information somehow? I'm thinking not, but i don't really know!