CBSA will have you in their system (as they've denied you entry previously)..
If they deny you entry upon arrival at YYC, you will not have to pay for your flight.
Since your not "admitted" to Canada, the airline must return you to your point of origin..
Keep in mind, that in this case your point of origin is Denver, not Philadelphia.. You might have to pay out of pocket for a DEN-PHL flight.